{"id":111,"date":"2023-06-21T13:22:34","date_gmt":"2023-06-21T13:22:34","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/gsu-collegealgebra\/chapter\/write-and-manipulate-inequalities\/"},"modified":"2023-09-07T16:37:42","modified_gmt":"2023-09-07T16:37:42","slug":"write-and-manipulate-inequalities","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/gsu-collegealgebra\/chapter\/write-and-manipulate-inequalities\/","title":{"raw":"\u25aa   Writing and Manipulating Inequalities","rendered":"\u25aa   Writing and Manipulating Inequalities"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n<h3>Learning Outcomes<\/h3>\r\n<ul>\r\n \t<li>Use interval notation to express inequalities.<\/li>\r\n \t<li>Use properties of inequalities.<\/li>\r\n<\/ul>\r\n<\/div>\r\nIndicating the solution to an inequality such as [latex]x\\ge 4[\/latex] can be achieved in several ways.\r\n\r\nWe can use a number line as shown below.\u00a0The blue ray begins at [latex]x=4[\/latex] and, as indicated by the arrowhead, continues to infinity, which illustrates that the solution set includes all real numbers greater than or equal to 4.\r\n\r\n<img class=\"aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/896\/2016\/10\/24225859\/CNX_CAT_Figure_02_07_002.jpg\" alt=\"A number line starting at zero with the last tick mark being labeled 11. There is a dot at the number 4 and an arrow extends toward the right.\" width=\"487\" height=\"49\" \/>\r\n\r\nWe can use <strong>set-builder notation<\/strong>: [latex]\\{x|x\\ge 4\\}[\/latex], which translates to \"all real numbers <em>x <\/em>such that <em>x <\/em>is greater than or equal to 4.\" Notice that braces are used to indicate a set.\r\n\r\nThe third method is <strong>interval notation<\/strong>, where solution sets are indicated with parentheses or brackets. The solutions to [latex]x\\ge 4[\/latex] are represented as [latex]\\left[4,\\infty \\right)[\/latex]. This is perhaps the most useful method as it applies to concepts studied later in this course and to other higher-level math courses.\r\n\r\nThe main concept to remember is that parentheses represent solutions greater or less than the number, and brackets represent solutions that are greater than or equal to or less than or equal to the number. Use parentheses to represent infinity or negative infinity, since positive and negative infinity are not numbers in the usual sense of the word and, therefore, cannot be \"equaled.\" A few examples of an <strong>interval<\/strong>, or a set of numbers in which a solution falls, are [latex]\\left[-2,6\\right)[\/latex], or all numbers between [latex]-2[\/latex] and [latex]6[\/latex], including [latex]-2[\/latex], but not including [latex]6[\/latex]; [latex]\\left(-1,0\\right)[\/latex], all real numbers between, but not including [latex]-1[\/latex] and [latex]0[\/latex]; and [latex]\\left(-\\infty ,1\\right][\/latex], all real numbers less than and including [latex]1[\/latex]. The table below\u00a0outlines the possibilities.\r\n<table summary=\"Table with 11 rows and 3 columns. Entries in the first row are: Set Indicated, Set-Builder Notation, Interval Notation. Entries in the second row are: All real numbers between a and b, but not including a and b; {x| a &lt; x &lt; b}; (a,b). The entries in the third row are: All real numbers greater than a, but not including a; {x| x &gt; a}; (a , infinity). The entries in the fourth row are: All real numbers less than b, but not including b; {x| x &lt; b}; (negative infinity, b). The entries in the fifth row are: All real numbers greater than a, including a; {x| x a}; [a, infinity). The entries in the sixth row are: All real numbers less than b, including b; {x| x b}; (negative infinity, b]. The entries in the seventh row are: All real numbers between a and b, including a; {x| a x &lt; b}; [a, b). The entries in the eighth row are: All real numbers between a and b, including b; {x| a &lt; x b}; (a, b]. The entries in the ninth row are: All real numbers between a and b, including a and b; {x| a x b}; [a, b]. The entries in the tenth row are: all real numbers less than a and greater than b; {x| x &lt; a and x &gt; b}; (negative infinity, a) union (b, infinity). The entries in the eleventh row are: All real numbers; {x| x is all real numbers}; (negative infinity, infinity).\">\r\n<thead>\r\n<tr>\r\n<th>Inequality<\/th>\r\n<th>Words<\/th>\r\n<th>Interval Notation<\/th>\r\n<\/tr>\r\n<\/thead>\r\n<tbody>\r\n<tr>\r\n<td>[latex]{a}\\lt{x}\\lt{ b}[\/latex]<\/td>\r\n<td>all real numbers between\u00a0<em>a<\/em> and <em>b<\/em>, not including a and b<\/td>\r\n<td>[latex]\\left(a,b\\right)[\/latex]<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>[latex]{x}\\gt{a}[\/latex]<\/td>\r\n<td>All real numbers greater than <em>a<\/em>, but not including <em>a<\/em><\/td>\r\n<td>[latex]\\left(a,\\infty \\right)[\/latex]<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>[latex]{x}\\lt{b}[\/latex]<\/td>\r\n<td>All real numbers less than <em>b<\/em>, but not including <em>b<\/em><\/td>\r\n<td>[latex]\\left(-\\infty ,b\\right)[\/latex]<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>[latex]{x}\\ge{a}[\/latex]<\/td>\r\n<td>All real numbers greater than <em>a<\/em>, including <em>a<\/em><\/td>\r\n<td>[latex]\\left[a,\\infty \\right)[\/latex]<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>[latex]{x}\\le{b}[\/latex]<\/td>\r\n<td>All real numbers less than <em>b<\/em>, including <em>b<\/em><\/td>\r\n<td>[latex]\\left(-\\infty ,b\\right][\/latex]<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>[latex]{a}\\le{x}\\lt{ b}[\/latex]<\/td>\r\n<td>All real numbers between <em>a <\/em>and<em> b<\/em>, including <em>a<\/em><\/td>\r\n<td>[latex]\\left[a,b\\right)[\/latex]<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>[latex]{a}\\lt{x}\\le{ b}[\/latex]<\/td>\r\n<td>All real numbers between <em>a<\/em> and <em>b<\/em>, including <em>b<\/em><\/td>\r\n<td>[latex]\\left(a,b\\right][\/latex]<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>[latex]{a}\\le{x}\\le{ b}[\/latex]<\/td>\r\n<td>All real numbers between <em>a <\/em>and <em>b<\/em>, including <em>a <\/em>and <em>b<\/em><\/td>\r\n<td>[latex]\\left[a,b\\right][\/latex]<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>[latex]{x}\\lt{a}\\text{ or }{x}\\gt{ b}[\/latex]<\/td>\r\n<td>All real numbers less than <em>a<\/em> or greater than <em>b<\/em><\/td>\r\n<td>[latex]\\left(-\\infty ,a\\right)\\cup \\left(b,\\infty \\right)[\/latex]<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>All real numbers<\/td>\r\n<td>All real numbers<\/td>\r\n<td>[latex]\\left(-\\infty ,\\infty \\right)[\/latex]<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<div class=\"textbox exercises\">\r\n<h3>Example: Using Interval Notation to Express an inequality<\/h3>\r\nUse interval notation to indicate all real numbers greater than or equal to [latex]-2[\/latex].\r\n\r\n[reveal-answer q=\"143041\"]Show Solution[\/reveal-answer]\r\n[hidden-answer a=\"143041\"]\r\n\r\nUse a bracket on the left of [latex]-2[\/latex] and parentheses after infinity: [latex]\\left[-2,\\infty \\right)[\/latex]. The bracket indicates that [latex]-2[\/latex] is included in the set with all real numbers greater than [latex]-2[\/latex] to infinity.\r\n\r\n[\/hidden-answer]\r\n\r\n<\/div>\r\n<div class=\"textbox exercises\">\r\n<h3>example: using interval notation to express an inequality<\/h3>\r\nDescribe the inequality [latex]x\\ge 4[\/latex] using interval notation\r\n[reveal-answer q=\"440342\"]Show Solution[\/reveal-answer]\r\n[hidden-answer a=\"440342\"]\r\n\r\nThe solutions to [latex]x\\ge 4[\/latex] are represented as [latex]\\left[4,\\infty \\right)[\/latex].\r\n\r\nNote the use of a bracket on the left because 4 is included in the solution set.\r\n\r\n[\/hidden-answer]\r\n\r\n<\/div>\r\n<div class=\"textbox key-takeaways\">\r\n<h3>Try It<\/h3>\r\nUse interval notation to indicate all real numbers between and including [latex]-3[\/latex] and [latex]5[\/latex].\r\n\r\n[reveal-answer q=\"814810\"]Show Solution[\/reveal-answer]\r\n[hidden-answer a=\"814810\"]\r\n\r\n[latex]\\left[-3,5\\right][\/latex]\r\n\r\n[\/hidden-answer]\r\n\r\n[ohm_question height=\"870\"]58-92604[\/ohm_question]\r\n\r\n<\/div>\r\n<div class=\"textbox exercises\">\r\n<h3>Example: Using Interval Notation to Express a compound inequality<\/h3>\r\nWrite the interval expressing all real numbers less than or equal to [latex]-1[\/latex] or greater than or equal to [latex]1[\/latex].\r\n\r\n[reveal-answer q=\"797079\"]Show Solution[\/reveal-answer]\r\n[hidden-answer a=\"797079\"]\r\n\r\nWe have to write two intervals for this example. The first interval must indicate all real numbers less than or equal to 1. So, this interval begins at [latex]-\\infty [\/latex] and ends at [latex]-1[\/latex], which is written as [latex]\\left(-\\infty ,-1\\right][\/latex].\r\n\r\nThe second interval must show all real numbers greater than or equal to [latex]1[\/latex], which is written as [latex]\\left[1,\\infty \\right)[\/latex]. However, we want to combine these two sets. We accomplish this by inserting the union symbol, [latex]\\cup [\/latex], between the two intervals.\r\n<div style=\"text-align: center;\">[latex]\\left(-\\infty ,-1\\right]\\cup \\left[1,\\infty \\right)[\/latex]<\/div>\r\n<div>[\/hidden-answer]<\/div>\r\n<\/div>\r\n<div class=\"textbox key-takeaways\">\r\n<h3>Try It<\/h3>\r\nExpress all real numbers less than [latex]-2[\/latex] or greater than or equal to 3 in interval notation.\r\n\r\n[reveal-answer q=\"729196\"]Show Solution[\/reveal-answer]\r\n[hidden-answer a=\"729196\"]\r\n\r\n[latex]\\left(-\\infty ,-2\\right)\\cup \\left[3,\\infty \\right)[\/latex]\r\n\r\n[\/hidden-answer]\r\n\r\n<\/div>\r\n<div class=\"textbox key-takeaways\">\r\n<h3>try it<\/h3>\r\nWe are going to look at a line with endpoints along the x-axis.\r\n<ol>\r\n \t<li>First we will adjust the left endpoint to (-15,0), and the right endpoint to (5,0)<img class=\"alignnone wp-image-6714\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/3794\/2016\/10\/08183340\/Screen-Shot-2019-07-08-at-11.26.00-AM.png\" alt=\"A line with endpoints at (-15,0) and (5,0).\" width=\"473\" height=\"161\" \/><\/li>\r\n \t<li>Write an inequality that represents the line you created.<\/li>\r\n<\/ol>\r\n[practice-area rows=\"1\"][\/practice-area]\r\n\r\n3. If we were to slide the left endpoint to (2,0), what do you think will happen to the line?\r\n\r\n[practice-area rows=\"1\"][\/practice-area]\r\n\r\n4. Now what if we were to slide the right endpoint to (11,0), what do you think will happen to the line? Sketch on a piece of paper what you think this new inequality graph will look like.\r\n\r\n[practice-area rows=\"1\"][\/practice-area]\r\n\r\n[reveal-answer q=\"748650\"]Show Solution[\/reveal-answer]\r\n[hidden-answer a=\"748650\"]\r\n\r\nWith endpoints (-15,0) and (5,0), the values for x on the line are between -15 and 5, so we can write [latex]-15&lt;x&lt;5[\/latex]. We made it a strict inequality because the dots on the endpoints of the lines are open.\r\n\r\nMoving the left endpoint towards the right endpoint shortens the line. Then moving the right endpoint away from the left endpoint lengthens the line again.\r\n\r\n<img class=\"alignnone wp-image-6715\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/3794\/2016\/10\/08183932\/Screen-Shot-2019-07-08-at-11.26.35-AM.png\" alt=\"Line with endpoints at (2,0) and (11,0).\" width=\"317\" height=\"128\" \/>\r\n\r\n[\/hidden-answer]\r\n\r\n<\/div>\r\n<div class=\"textbox key-takeaways\">\r\n<h3>think about it<\/h3>\r\nIn the previous examples you were given an inequality or a description of one with words and asked to draw the corresponding graph and write the interval. In this example you are given an interval and\u00a0asked to write the inequality and draw the graph.\r\n\r\nGiven [latex]\\left(-\\infty,10\\right)[\/latex], write the associated inequality and draw the graph.\r\n\r\nIn the box below, write down whether you think it will be easier to draw the graph first or write the inequality first.\r\n\r\n[practice-area rows=\"1\"][\/practice-area]\r\n[reveal-answer q=\"179859\"]Show Solution[\/reveal-answer]\r\n[hidden-answer a=\"179859\"]\r\n\r\nWe will draw the graph first.\r\n\r\nThe interval reads \"all real numbers less\u00a0than 10,\" so we will start by placing an open\u00a0dot on 10 and drawing a line to the left\u00a0with an arrow indicating the solution continues to negative infinity.\r\n\r\n<img class=\"aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/121\/2016\/06\/01182811\/4.png\" alt=\"An open circle on 10 and a line going from 10 to all numbers below 10.\" width=\"339\" height=\"95\" \/>\r\n\r\nTo write the inequality, we will use &lt; since the parentheses indicate that 10 is not included. [latex]x&lt;10[\/latex]\r\n\r\n[\/hidden-answer]\r\n\r\n<\/div>\r\nIn the following video, you will see examples of how to write inequalities in the three ways presented here: as an inequality, in interval notation, and with a graph.\r\n\r\nhttps:\/\/youtu.be\/X0xrHKgbDT0\r\n<h2>Using the Properties of Inequalities<\/h2>\r\n<div class=\"textbox examples\">\r\n<h3>recall solving multi-step equations<\/h3>\r\nWhen solving inequalities, all the properties of equality and real numbers apply. We are permitted to add, subtract, multiply, or divide the same quantity to\u00a0<strong>both sides<\/strong> of the inequality.\r\n\r\nLikewise, we may apply the distributive, commutative, and associative properties as desired to help isolate the variable.\r\n\r\nWe may also distribute the LCD on both sides of an inequality to eliminate denominators.\r\n\r\nThe only difference is that if we multiply or divide\u00a0<strong>both sides<\/strong> by a negative quantity, we must reverse the direction of the inequality symbol.\r\n\r\n<\/div>\r\nWhen we work with inequalities, we can usually treat them similarly to but not exactly as we treat equations. We can use the <strong>addition property<\/strong> and the <strong>multiplication property<\/strong> to help us solve them. The one exception is when we multiply or divide by a negative number, we must reverse the inequality symbol.\r\n<div class=\"textbox\">\r\n<h3>A General Note: Properties of Inequalities<\/h3>\r\n<p style=\"text-align: center;\">[latex]\\begin{array}{ll}\\text{Addition Property}\\hfill&amp; \\text{If }a&lt; b,\\text{ then }a+c&lt; b+c.\\hfill \\\\ \\hfill &amp; \\hfill \\\\ \\text{Multiplication Property}\\hfill &amp; \\text{If }a&lt; b\\text{ and }c&gt; 0,\\text{ then }ac&lt; bc.\\hfill \\\\ \\hfill &amp; \\text{If }a&lt; b\\text{ and }c&lt; 0,\\text{ then }ac&gt; bc.\\hfill \\end{array}[\/latex]<\/p>\r\nThese properties also apply to [latex]a\\le b[\/latex], [latex]a&gt;b[\/latex], and [latex]a\\ge b[\/latex].\r\n\r\n<\/div>\r\n<div class=\"textbox exercises\">\r\n<h3>Example: Demonstrating the Addition Property<\/h3>\r\nIllustrate the addition property for inequalities by solving each of the following:\r\n<ol>\r\n \t<li>[latex]x - 15&lt;4[\/latex]<\/li>\r\n \t<li>[latex]6\\ge x - 1[\/latex]<\/li>\r\n \t<li>[latex]x+7&gt;9[\/latex]<\/li>\r\n<\/ol>\r\n[reveal-answer q=\"105622\"]Show Solution[\/reveal-answer]\r\n[hidden-answer a=\"105622\"]\r\n\r\nThe addition property for inequalities states that if an inequality exists, adding or subtracting the same number on both sides does not change the inequality.\r\n\r\n1.\r\n\r\n[latex]\\begin{array}{ll}x - 15&lt;4\\hfill &amp; \\hfill \\\\ x - 15+15&lt;4+15 \\hfill &amp; \\text{Add 15 to both sides.}\\hfill \\\\ x&lt;19\\hfill &amp; \\hfill \\end{array}[\/latex]\r\n\r\n2.\r\n\r\n[latex]\\begin{array}{ll}6\\ge x - 1\\hfill &amp; \\hfill \\\\ 6+1\\ge x - 1+1\\hfill &amp; \\text{Add 1 to both sides}.\\hfill \\\\ 7\\ge x\\hfill &amp; \\hfill \\end{array}[\/latex]\r\n\r\n3.\r\n\r\n[latex]\\begin{array}{ll}x+7&gt;9\\hfill &amp; \\hfill \\\\ x+7 - 7&gt;9 - 7\\hfill &amp; \\text{Subtract 7 from both sides}.\\hfill \\\\ x&gt;2\\hfill &amp; \\hfill \\end{array}[\/latex]\r\n\r\n[\/hidden-answer]\r\n\r\n<\/div>\r\n<div class=\"textbox key-takeaways\">\r\n<h3>Try It<\/h3>\r\nSolve [latex]3x - 2&lt;1[\/latex].\r\n\r\n[reveal-answer q=\"68318\"]Show Solution[\/reveal-answer]\r\n[hidden-answer a=\"68318\"]\r\n\r\n[latex]x&lt;1[\/latex]\r\n\r\n[\/hidden-answer]\r\n\r\n[ohm_question height=\"235\"]92605[\/ohm_question]\r\n\r\n<\/div>\r\n<div class=\"textbox exercises\">\r\n<h3>Example: Demonstrating the Multiplication Property<\/h3>\r\nIllustrate the multiplication property for inequalities by solving each of the following:\r\n<ol>\r\n \t<li>[latex]3x&lt;6[\/latex]<\/li>\r\n \t<li>[latex]-2x - 1\\ge 5[\/latex]<\/li>\r\n \t<li>[latex]5-x&gt;10[\/latex]<\/li>\r\n<\/ol>\r\n[reveal-answer q=\"749552\"]Show Solution[\/reveal-answer]\r\n[hidden-answer a=\"749552\"]\r\n\r\n1.\r\n\r\n[latex]\\begin{array}{l}3x&lt;6\\hfill \\\\ \\frac{1}{3}\\left(3x\\right)&lt;\\left(6\\right)\\frac{1}{3}\\hfill \\\\ x&lt;2\\hfill \\end{array}[\/latex]\r\n\r\n2.\r\n\r\n[latex]\\begin{array}{ll}-2x - 1\\ge 5\\hfill &amp; \\hfill \\\\ -2x\\ge 6\\hfill &amp; \\hfill \\\\ \\left(-\\frac{1}{2}\\right)\\left(-2x\\right)\\ge \\left(6\\right)\\left(-\\frac{1}{2}\\right)\\hfill &amp; \\text{Multiply by }-\\frac{1}{2}.\\hfill \\\\ x\\le -3\\hfill &amp; \\text{Reverse the inequality}.\\hfill \\end{array}[\/latex]\r\n\r\n3.\r\n\r\n[latex]\\begin{array}{ll}5-x&gt;10\\hfill &amp; \\hfill \\\\ -x&gt;5\\hfill &amp; \\hfill \\\\ \\left(-1\\right)\\left(-x\\right)&gt;\\left(5\\right)\\left(-1\\right)\\hfill &amp; \\text{Multiply by }-1.\\hfill \\\\ x&lt;-5\\hfill &amp; \\text{Reverse the inequality}.\\hfill \\end{array}[\/latex]\r\n<div>[\/hidden-answer]<\/div>\r\n<\/div>\r\n<div class=\"textbox key-takeaways\">\r\n<h3>Try It<\/h3>\r\nSolve [latex]4x+7\\ge 2x - 3[\/latex].\r\n\r\n[reveal-answer q=\"32307\"]Show Solution[\/reveal-answer]\r\n[hidden-answer a=\"32307\"]\r\n\r\n[latex]x\\ge -5[\/latex][\/hidden-answer]\r\n\r\n[ohm_question height=\"265\"]92606[\/ohm_question]\r\n\r\n<\/div>\r\nWatch the following two videos for a demonstration of using the addition and multiplication properties to solve inequalities.\r\n\r\n[embed]https:\/\/youtu.be\/1Z22Xh66VFM[\/embed]\r\n\r\n[embed]https:\/\/youtu.be\/RBonYKvTCLU[\/embed]\r\n<h2>Solving Inequalities in One Variable Algebraically<\/h2>\r\nAs the examples have shown, we can perform the same operations on both sides of an inequality, just as we do with equations; we combine like terms and perform operations. To solve, we isolate the variable.\r\n<div class=\"textbox exercises\">\r\n<h3>Example: Solving an Inequality Algebraically<\/h3>\r\nSolve the inequality: [latex]13 - 7x\\ge 10x - 4[\/latex].\r\n\r\n[reveal-answer q=\"453286\"]Show Solution[\/reveal-answer]\r\n[hidden-answer a=\"453286\"]\r\n\r\nSolving this inequality is similar to solving an equation up until the last step.\r\n<div style=\"text-align: center;\">[latex]\\begin{array}{ll}13 - 7x\\ge 10x - 4\\hfill &amp; \\hfill \\\\ 13 - 17x\\ge -4\\hfill &amp; \\text{Move variable terms to one side of the inequality}.\\hfill \\\\ -17x\\ge -17\\hfill &amp; \\text{Isolate the variable term}.\\hfill \\\\ x\\le 1\\hfill &amp; \\text{Dividing both sides by }-17\\text{ reverses the inequality}.\\hfill \\end{array}[\/latex]<\/div>\r\nThe solution set is given by the interval [latex]\\left(-\\infty ,1\\right][\/latex], or all real numbers less than and including 1.\r\n\r\n[\/hidden-answer]\r\n\r\n<\/div>\r\n<div class=\"textbox key-takeaways\">\r\n<h3>Try It<\/h3>\r\nSolve the inequality and write the answer using interval notation: [latex]-x+4&lt;\\frac{1}{2}x+1[\/latex].\r\n\r\n[reveal-answer q=\"703883\"]Show Solution[\/reveal-answer]\r\n[hidden-answer a=\"703883\"]\r\n\r\n[latex]\\left(2,\\infty \\right)[\/latex][\/hidden-answer]\r\n\r\n[ohm_question height=\"210\"]92607[\/ohm_question]\r\n\r\n<\/div>\r\n<div class=\"textbox exercises\">\r\n<h3>Example: Solving an Inequality with Fractions<\/h3>\r\nSolve the following inequality and write the answer in interval notation: [latex]-\\frac{3}{4}x\\ge -\\frac{5}{8}+\\frac{2}{3}x[\/latex].\r\n\r\n[reveal-answer q=\"37354\"]Show Solution[\/reveal-answer]\r\n[hidden-answer a=\"37354\"]\r\nWe begin solving in the same way we do when solving an equation.\r\n<div style=\"text-align: center;\">[latex]\\begin{array}{ll}-\\frac{3}{4}x\\ge -\\frac{5}{8}+\\frac{2}{3}x\\hfill &amp; \\hfill \\\\ -\\frac{3}{4}x-\\frac{2}{3}x\\ge -\\frac{5}{8}\\hfill &amp; \\text{Put variable terms on one side}.\\hfill \\\\ -\\frac{9}{12}x-\\frac{8}{12}x\\ge -\\frac{5}{8}\\hfill &amp; \\text{Write fractions with common denominator}.\\hfill \\\\ -\\frac{17}{12}x\\ge -\\frac{5}{8}\\hfill &amp; \\hfill \\\\ x\\le -\\frac{5}{8}\\left(-\\frac{12}{17}\\right)\\hfill &amp; \\text{Multiplying by a negative number reverses the inequality}.\\hfill \\\\ x\\le \\frac{15}{34}\\hfill &amp; \\hfill \\end{array}[\/latex]<\/div>\r\nThe solution set is the interval [latex]\\left(-\\infty ,\\frac{15}{34}\\right][\/latex].\r\n\r\n[\/hidden-answer]\r\n\r\n<\/div>\r\n<div class=\"textbox key-takeaways\">\r\n<h3>Try It<\/h3>\r\nSolve the inequality and write the answer in interval notation: [latex]-\\frac{5}{6}x\\le \\frac{3}{4}+\\frac{8}{3}x[\/latex].\r\n\r\n[reveal-answer q=\"524889\"]Show Solution[\/reveal-answer]\r\n[hidden-answer a=\"524889\"]\r\n\r\n[latex]\\left[-\\frac{3}{14},\\infty \\right)[\/latex]\r\n\r\n[\/hidden-answer]\r\n\r\n[ohm_question height=\"340\"]72891[\/ohm_question]\r\n\r\n<\/div>","rendered":"<div class=\"textbox learning-objectives\">\n<h3>Learning Outcomes<\/h3>\n<ul>\n<li>Use interval notation to express inequalities.<\/li>\n<li>Use properties of inequalities.<\/li>\n<\/ul>\n<\/div>\n<p>Indicating the solution to an inequality such as [latex]x\\ge 4[\/latex] can be achieved in several ways.<\/p>\n<p>We can use a number line as shown below.\u00a0The blue ray begins at [latex]x=4[\/latex] and, as indicated by the arrowhead, continues to infinity, which illustrates that the solution set includes all real numbers greater than or equal to 4.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/896\/2016\/10\/24225859\/CNX_CAT_Figure_02_07_002.jpg\" alt=\"A number line starting at zero with the last tick mark being labeled 11. There is a dot at the number 4 and an arrow extends toward the right.\" width=\"487\" height=\"49\" \/><\/p>\n<p>We can use <strong>set-builder notation<\/strong>: [latex]\\{x|x\\ge 4\\}[\/latex], which translates to &#8220;all real numbers <em>x <\/em>such that <em>x <\/em>is greater than or equal to 4.&#8221; Notice that braces are used to indicate a set.<\/p>\n<p>The third method is <strong>interval notation<\/strong>, where solution sets are indicated with parentheses or brackets. The solutions to [latex]x\\ge 4[\/latex] are represented as [latex]\\left[4,\\infty \\right)[\/latex]. This is perhaps the most useful method as it applies to concepts studied later in this course and to other higher-level math courses.<\/p>\n<p>The main concept to remember is that parentheses represent solutions greater or less than the number, and brackets represent solutions that are greater than or equal to or less than or equal to the number. Use parentheses to represent infinity or negative infinity, since positive and negative infinity are not numbers in the usual sense of the word and, therefore, cannot be &#8220;equaled.&#8221; A few examples of an <strong>interval<\/strong>, or a set of numbers in which a solution falls, are [latex]\\left[-2,6\\right)[\/latex], or all numbers between [latex]-2[\/latex] and [latex]6[\/latex], including [latex]-2[\/latex], but not including [latex]6[\/latex]; [latex]\\left(-1,0\\right)[\/latex], all real numbers between, but not including [latex]-1[\/latex] and [latex]0[\/latex]; and [latex]\\left(-\\infty ,1\\right][\/latex], all real numbers less than and including [latex]1[\/latex]. The table below\u00a0outlines the possibilities.<\/p>\n<table summary=\"Table with 11 rows and 3 columns. Entries in the first row are: Set Indicated, Set-Builder Notation, Interval Notation. Entries in the second row are: All real numbers between a and b, but not including a and b; {x| a &lt; x &lt; b}; (a,b). The entries in the third row are: All real numbers greater than a, but not including a; {x| x &gt; a}; (a , infinity). The entries in the fourth row are: All real numbers less than b, but not including b; {x| x &lt; b}; (negative infinity, b). The entries in the fifth row are: All real numbers greater than a, including a; {x| x a}; [a, infinity). The entries in the sixth row are: All real numbers less than b, including b; {x| x b}; (negative infinity, b]. The entries in the seventh row are: All real numbers between a and b, including a; {x| a x &lt; b}; [a, b). The entries in the eighth row are: All real numbers between a and b, including b; {x| a &lt; x b}; (a, b]. The entries in the ninth row are: All real numbers between a and b, including a and b; {x| a x b}; [a, b]. The entries in the tenth row are: all real numbers less than a and greater than b; {x| x &lt; a and x &gt; b}; (negative infinity, a) union (b, infinity). The entries in the eleventh row are: All real numbers; {x| x is all real numbers}; (negative infinity, infinity).\">\n<thead>\n<tr>\n<th>Inequality<\/th>\n<th>Words<\/th>\n<th>Interval Notation<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>[latex]{a}\\lt{x}\\lt{ b}[\/latex]<\/td>\n<td>all real numbers between\u00a0<em>a<\/em> and <em>b<\/em>, not including a and b<\/td>\n<td>[latex]\\left(a,b\\right)[\/latex]<\/td>\n<\/tr>\n<tr>\n<td>[latex]{x}\\gt{a}[\/latex]<\/td>\n<td>All real numbers greater than <em>a<\/em>, but not including <em>a<\/em><\/td>\n<td>[latex]\\left(a,\\infty \\right)[\/latex]<\/td>\n<\/tr>\n<tr>\n<td>[latex]{x}\\lt{b}[\/latex]<\/td>\n<td>All real numbers less than <em>b<\/em>, but not including <em>b<\/em><\/td>\n<td>[latex]\\left(-\\infty ,b\\right)[\/latex]<\/td>\n<\/tr>\n<tr>\n<td>[latex]{x}\\ge{a}[\/latex]<\/td>\n<td>All real numbers greater than <em>a<\/em>, including <em>a<\/em><\/td>\n<td>[latex]\\left[a,\\infty \\right)[\/latex]<\/td>\n<\/tr>\n<tr>\n<td>[latex]{x}\\le{b}[\/latex]<\/td>\n<td>All real numbers less than <em>b<\/em>, including <em>b<\/em><\/td>\n<td>[latex]\\left(-\\infty ,b\\right][\/latex]<\/td>\n<\/tr>\n<tr>\n<td>[latex]{a}\\le{x}\\lt{ b}[\/latex]<\/td>\n<td>All real numbers between <em>a <\/em>and<em> b<\/em>, including <em>a<\/em><\/td>\n<td>[latex]\\left[a,b\\right)[\/latex]<\/td>\n<\/tr>\n<tr>\n<td>[latex]{a}\\lt{x}\\le{ b}[\/latex]<\/td>\n<td>All real numbers between <em>a<\/em> and <em>b<\/em>, including <em>b<\/em><\/td>\n<td>[latex]\\left(a,b\\right][\/latex]<\/td>\n<\/tr>\n<tr>\n<td>[latex]{a}\\le{x}\\le{ b}[\/latex]<\/td>\n<td>All real numbers between <em>a <\/em>and <em>b<\/em>, including <em>a <\/em>and <em>b<\/em><\/td>\n<td>[latex]\\left[a,b\\right][\/latex]<\/td>\n<\/tr>\n<tr>\n<td>[latex]{x}\\lt{a}\\text{ or }{x}\\gt{ b}[\/latex]<\/td>\n<td>All real numbers less than <em>a<\/em> or greater than <em>b<\/em><\/td>\n<td>[latex]\\left(-\\infty ,a\\right)\\cup \\left(b,\\infty \\right)[\/latex]<\/td>\n<\/tr>\n<tr>\n<td>All real numbers<\/td>\n<td>All real numbers<\/td>\n<td>[latex]\\left(-\\infty ,\\infty \\right)[\/latex]<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<div class=\"textbox exercises\">\n<h3>Example: Using Interval Notation to Express an inequality<\/h3>\n<p>Use interval notation to indicate all real numbers greater than or equal to [latex]-2[\/latex].<\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q143041\">Show Solution<\/span><\/p>\n<div id=\"q143041\" class=\"hidden-answer\" style=\"display: none\">\n<p>Use a bracket on the left of [latex]-2[\/latex] and parentheses after infinity: [latex]\\left[-2,\\infty \\right)[\/latex]. The bracket indicates that [latex]-2[\/latex] is included in the set with all real numbers greater than [latex]-2[\/latex] to infinity.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<div class=\"textbox exercises\">\n<h3>example: using interval notation to express an inequality<\/h3>\n<p>Describe the inequality [latex]x\\ge 4[\/latex] using interval notation<\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q440342\">Show Solution<\/span><\/p>\n<div id=\"q440342\" class=\"hidden-answer\" style=\"display: none\">\n<p>The solutions to [latex]x\\ge 4[\/latex] are represented as [latex]\\left[4,\\infty \\right)[\/latex].<\/p>\n<p>Note the use of a bracket on the left because 4 is included in the solution set.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<div class=\"textbox key-takeaways\">\n<h3>Try It<\/h3>\n<p>Use interval notation to indicate all real numbers between and including [latex]-3[\/latex] and [latex]5[\/latex].<\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q814810\">Show Solution<\/span><\/p>\n<div id=\"q814810\" class=\"hidden-answer\" style=\"display: none\">\n<p>[latex]\\left[-3,5\\right][\/latex]<\/p>\n<\/div>\n<\/div>\n<p><iframe loading=\"lazy\" id=\"ohm58\" class=\"resizable\" src=\"https:\/\/ohm.lumenlearning.com\/multiembedq.php?id=58-92604&theme=oea&iframe_resize_id=ohm58&show_question_numbers\" width=\"100%\" height=\"870\"><\/iframe><\/p>\n<\/div>\n<div class=\"textbox exercises\">\n<h3>Example: Using Interval Notation to Express a compound inequality<\/h3>\n<p>Write the interval expressing all real numbers less than or equal to [latex]-1[\/latex] or greater than or equal to [latex]1[\/latex].<\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q797079\">Show Solution<\/span><\/p>\n<div id=\"q797079\" class=\"hidden-answer\" style=\"display: none\">\n<p>We have to write two intervals for this example. The first interval must indicate all real numbers less than or equal to 1. So, this interval begins at [latex]-\\infty[\/latex] and ends at [latex]-1[\/latex], which is written as [latex]\\left(-\\infty ,-1\\right][\/latex].<\/p>\n<p>The second interval must show all real numbers greater than or equal to [latex]1[\/latex], which is written as [latex]\\left[1,\\infty \\right)[\/latex]. However, we want to combine these two sets. We accomplish this by inserting the union symbol, [latex]\\cup[\/latex], between the two intervals.<\/p>\n<div style=\"text-align: center;\">[latex]\\left(-\\infty ,-1\\right]\\cup \\left[1,\\infty \\right)[\/latex]<\/div>\n<div><\/div>\n<\/div>\n<\/div>\n<\/div>\n<div class=\"textbox key-takeaways\">\n<h3>Try It<\/h3>\n<p>Express all real numbers less than [latex]-2[\/latex] or greater than or equal to 3 in interval notation.<\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q729196\">Show Solution<\/span><\/p>\n<div id=\"q729196\" class=\"hidden-answer\" style=\"display: none\">\n<p>[latex]\\left(-\\infty ,-2\\right)\\cup \\left[3,\\infty \\right)[\/latex]<\/p>\n<\/div>\n<\/div>\n<\/div>\n<div class=\"textbox key-takeaways\">\n<h3>try it<\/h3>\n<p>We are going to look at a line with endpoints along the x-axis.<\/p>\n<ol>\n<li>First we will adjust the left endpoint to (-15,0), and the right endpoint to (5,0)<img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-6714\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/3794\/2016\/10\/08183340\/Screen-Shot-2019-07-08-at-11.26.00-AM.png\" alt=\"A line with endpoints at (-15,0) and (5,0).\" width=\"473\" height=\"161\" \/><\/li>\n<li>Write an inequality that represents the line you created.<\/li>\n<\/ol>\n<p><textarea aria-label=\"Your Answer\" rows=\"1\"><\/textarea><\/p>\n<p>3. If we were to slide the left endpoint to (2,0), what do you think will happen to the line?<\/p>\n<p><textarea aria-label=\"Your Answer\" rows=\"1\"><\/textarea><\/p>\n<p>4. Now what if we were to slide the right endpoint to (11,0), what do you think will happen to the line? Sketch on a piece of paper what you think this new inequality graph will look like.<\/p>\n<p><textarea aria-label=\"Your Answer\" rows=\"1\"><\/textarea><\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q748650\">Show Solution<\/span><\/p>\n<div id=\"q748650\" class=\"hidden-answer\" style=\"display: none\">\n<p>With endpoints (-15,0) and (5,0), the values for x on the line are between -15 and 5, so we can write [latex]-15<x<5[\/latex]. We made it a strict inequality because the dots on the endpoints of the lines are open.\n\nMoving the left endpoint towards the right endpoint shortens the line. Then moving the right endpoint away from the left endpoint lengthens the line again.\n\n<img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-6715\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/3794\/2016\/10\/08183932\/Screen-Shot-2019-07-08-at-11.26.35-AM.png\" alt=\"Line with endpoints at (2,0) and (11,0).\" width=\"317\" height=\"128\" \/><\/p>\n<\/div>\n<\/div>\n<\/div>\n<div class=\"textbox key-takeaways\">\n<h3>think about it<\/h3>\n<p>In the previous examples you were given an inequality or a description of one with words and asked to draw the corresponding graph and write the interval. In this example you are given an interval and\u00a0asked to write the inequality and draw the graph.<\/p>\n<p>Given [latex]\\left(-\\infty,10\\right)[\/latex], write the associated inequality and draw the graph.<\/p>\n<p>In the box below, write down whether you think it will be easier to draw the graph first or write the inequality first.<\/p>\n<p><textarea aria-label=\"Your Answer\" rows=\"1\"><\/textarea><\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q179859\">Show Solution<\/span><\/p>\n<div id=\"q179859\" class=\"hidden-answer\" style=\"display: none\">\n<p>We will draw the graph first.<\/p>\n<p>The interval reads &#8220;all real numbers less\u00a0than 10,&#8221; so we will start by placing an open\u00a0dot on 10 and drawing a line to the left\u00a0with an arrow indicating the solution continues to negative infinity.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/121\/2016\/06\/01182811\/4.png\" alt=\"An open circle on 10 and a line going from 10 to all numbers below 10.\" width=\"339\" height=\"95\" \/><\/p>\n<p>To write the inequality, we will use &lt; since the parentheses indicate that 10 is not included. [latex]x<10[\/latex]\n\n<\/div>\n<\/div>\n<\/div>\n<p>In the following video, you will see examples of how to write inequalities in the three ways presented here: as an inequality, in interval notation, and with a graph.<\/p>\n<p><iframe loading=\"lazy\" id=\"oembed-3\" title=\"Ex: Graph Basic Inequalities and Express Using Interval Notation\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/X0xrHKgbDT0?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<h2>Using the Properties of Inequalities<\/h2>\n<div class=\"textbox examples\">\n<h3>recall solving multi-step equations<\/h3>\n<p>When solving inequalities, all the properties of equality and real numbers apply. We are permitted to add, subtract, multiply, or divide the same quantity to\u00a0<strong>both sides<\/strong> of the inequality.<\/p>\n<p>Likewise, we may apply the distributive, commutative, and associative properties as desired to help isolate the variable.<\/p>\n<p>We may also distribute the LCD on both sides of an inequality to eliminate denominators.<\/p>\n<p>The only difference is that if we multiply or divide\u00a0<strong>both sides<\/strong> by a negative quantity, we must reverse the direction of the inequality symbol.<\/p>\n<\/div>\n<p>When we work with inequalities, we can usually treat them similarly to but not exactly as we treat equations. We can use the <strong>addition property<\/strong> and the <strong>multiplication property<\/strong> to help us solve them. The one exception is when we multiply or divide by a negative number, we must reverse the inequality symbol.<\/p>\n<div class=\"textbox\">\n<h3>A General Note: Properties of Inequalities<\/h3>\n<p style=\"text-align: center;\">[latex]\\begin{array}{ll}\\text{Addition Property}\\hfill& \\text{If }a< b,\\text{ then }a+c< b+c.\\hfill \\\\ \\hfill & \\hfill \\\\ \\text{Multiplication Property}\\hfill & \\text{If }a< b\\text{ and }c> 0,\\text{ then }ac< bc.\\hfill \\\\ \\hfill & \\text{If }a< b\\text{ and }c< 0,\\text{ then }ac> bc.\\hfill \\end{array}[\/latex]<\/p>\n<p>These properties also apply to [latex]a\\le b[\/latex], [latex]a>b[\/latex], and [latex]a\\ge b[\/latex].<\/p>\n<\/div>\n<div class=\"textbox exercises\">\n<h3>Example: Demonstrating the Addition Property<\/h3>\n<p>Illustrate the addition property for inequalities by solving each of the following:<\/p>\n<ol>\n<li>[latex]x - 15<4[\/latex]<\/li>\n<li>[latex]6\\ge x - 1[\/latex]<\/li>\n<li>[latex]x+7>9[\/latex]<\/li>\n<\/ol>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q105622\">Show Solution<\/span><\/p>\n<div id=\"q105622\" class=\"hidden-answer\" style=\"display: none\">\n<p>The addition property for inequalities states that if an inequality exists, adding or subtracting the same number on both sides does not change the inequality.<\/p>\n<p>1.<\/p>\n<p>[latex]\\begin{array}{ll}x - 15<4\\hfill & \\hfill \\\\ x - 15+15<4+15 \\hfill & \\text{Add 15 to both sides.}\\hfill \\\\ x<19\\hfill & \\hfill \\end{array}[\/latex]\n\n2.\n\n[latex]\\begin{array}{ll}6\\ge x - 1\\hfill & \\hfill \\\\ 6+1\\ge x - 1+1\\hfill & \\text{Add 1 to both sides}.\\hfill \\\\ 7\\ge x\\hfill & \\hfill \\end{array}[\/latex]\n\n3.\n\n[latex]\\begin{array}{ll}x+7>9\\hfill & \\hfill \\\\ x+7 - 7>9 - 7\\hfill & \\text{Subtract 7 from both sides}.\\hfill \\\\ x>2\\hfill & \\hfill \\end{array}[\/latex]<\/p>\n<\/div>\n<\/div>\n<\/div>\n<div class=\"textbox key-takeaways\">\n<h3>Try It<\/h3>\n<p>Solve [latex]3x - 2<1[\/latex].\n\n\n\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q68318\">Show Solution<\/span><\/p>\n<div id=\"q68318\" class=\"hidden-answer\" style=\"display: none\">\n<p>[latex]x<1[\/latex]\n\n<\/div>\n<\/div>\n<p><iframe loading=\"lazy\" id=\"ohm92605\" class=\"resizable\" src=\"https:\/\/ohm.lumenlearning.com\/multiembedq.php?id=92605&theme=oea&iframe_resize_id=ohm92605&show_question_numbers\" width=\"100%\" height=\"235\"><\/iframe><\/p>\n<\/div>\n<div class=\"textbox exercises\">\n<h3>Example: Demonstrating the Multiplication Property<\/h3>\n<p>Illustrate the multiplication property for inequalities by solving each of the following:<\/p>\n<ol>\n<li>[latex]3x<6[\/latex]<\/li>\n<li>[latex]-2x - 1\\ge 5[\/latex]<\/li>\n<li>[latex]5-x>10[\/latex]<\/li>\n<\/ol>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q749552\">Show Solution<\/span><\/p>\n<div id=\"q749552\" class=\"hidden-answer\" style=\"display: none\">\n<p>1.<\/p>\n<p>[latex]\\begin{array}{l}3x<6\\hfill \\\\ \\frac{1}{3}\\left(3x\\right)<\\left(6\\right)\\frac{1}{3}\\hfill \\\\ x<2\\hfill \\end{array}[\/latex]\n\n2.\n\n[latex]\\begin{array}{ll}-2x - 1\\ge 5\\hfill & \\hfill \\\\ -2x\\ge 6\\hfill & \\hfill \\\\ \\left(-\\frac{1}{2}\\right)\\left(-2x\\right)\\ge \\left(6\\right)\\left(-\\frac{1}{2}\\right)\\hfill & \\text{Multiply by }-\\frac{1}{2}.\\hfill \\\\ x\\le -3\\hfill & \\text{Reverse the inequality}.\\hfill \\end{array}[\/latex]\n\n3.\n\n[latex]\\begin{array}{ll}5-x>10\\hfill & \\hfill \\\\ -x>5\\hfill & \\hfill \\\\ \\left(-1\\right)\\left(-x\\right)>\\left(5\\right)\\left(-1\\right)\\hfill & \\text{Multiply by }-1.\\hfill \\\\ x<-5\\hfill & \\text{Reverse the inequality}.\\hfill \\end{array}[\/latex]\n\n\n<div><\/div>\n<\/div>\n<\/div>\n<\/div>\n<div class=\"textbox key-takeaways\">\n<h3>Try It<\/h3>\n<p>Solve [latex]4x+7\\ge 2x - 3[\/latex].<\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q32307\">Show Solution<\/span><\/p>\n<div id=\"q32307\" class=\"hidden-answer\" style=\"display: none\">\n<p>[latex]x\\ge -5[\/latex]<\/p><\/div>\n<\/div>\n<p><iframe loading=\"lazy\" id=\"ohm92606\" class=\"resizable\" src=\"https:\/\/ohm.lumenlearning.com\/multiembedq.php?id=92606&theme=oea&iframe_resize_id=ohm92606&show_question_numbers\" width=\"100%\" height=\"265\"><\/iframe><\/p>\n<\/div>\n<p>Watch the following two videos for a demonstration of using the addition and multiplication properties to solve inequalities.<\/p>\n<p><iframe loading=\"lazy\" id=\"oembed-1\" title=\"Ex:  Solving One Step Inequalities by Adding and Subtracting (Variable Left Side)\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/1Z22Xh66VFM?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<p><iframe loading=\"lazy\" id=\"oembed-2\" title=\"Ex:  Solving One Step Inequalities by Adding and Subtracting (Variable Right Side)\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/RBonYKvTCLU?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<h2>Solving Inequalities in One Variable Algebraically<\/h2>\n<p>As the examples have shown, we can perform the same operations on both sides of an inequality, just as we do with equations; we combine like terms and perform operations. To solve, we isolate the variable.<\/p>\n<div class=\"textbox exercises\">\n<h3>Example: Solving an Inequality Algebraically<\/h3>\n<p>Solve the inequality: [latex]13 - 7x\\ge 10x - 4[\/latex].<\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q453286\">Show Solution<\/span><\/p>\n<div id=\"q453286\" class=\"hidden-answer\" style=\"display: none\">\n<p>Solving this inequality is similar to solving an equation up until the last step.<\/p>\n<div style=\"text-align: center;\">[latex]\\begin{array}{ll}13 - 7x\\ge 10x - 4\\hfill & \\hfill \\\\ 13 - 17x\\ge -4\\hfill & \\text{Move variable terms to one side of the inequality}.\\hfill \\\\ -17x\\ge -17\\hfill & \\text{Isolate the variable term}.\\hfill \\\\ x\\le 1\\hfill & \\text{Dividing both sides by }-17\\text{ reverses the inequality}.\\hfill \\end{array}[\/latex]<\/div>\n<p>The solution set is given by the interval [latex]\\left(-\\infty ,1\\right][\/latex], or all real numbers less than and including 1.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<div class=\"textbox key-takeaways\">\n<h3>Try It<\/h3>\n<p>Solve the inequality and write the answer using interval notation: [latex]-x+4<\\frac{1}{2}x+1[\/latex].\n\n\n\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q703883\">Show Solution<\/span><\/p>\n<div id=\"q703883\" class=\"hidden-answer\" style=\"display: none\">\n<p>[latex]\\left(2,\\infty \\right)[\/latex]<\/p><\/div>\n<\/div>\n<p><iframe loading=\"lazy\" id=\"ohm92607\" class=\"resizable\" src=\"https:\/\/ohm.lumenlearning.com\/multiembedq.php?id=92607&theme=oea&iframe_resize_id=ohm92607&show_question_numbers\" width=\"100%\" height=\"210\"><\/iframe><\/p>\n<\/div>\n<div class=\"textbox exercises\">\n<h3>Example: Solving an Inequality with Fractions<\/h3>\n<p>Solve the following inequality and write the answer in interval notation: [latex]-\\frac{3}{4}x\\ge -\\frac{5}{8}+\\frac{2}{3}x[\/latex].<\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q37354\">Show Solution<\/span><\/p>\n<div id=\"q37354\" class=\"hidden-answer\" style=\"display: none\">\nWe begin solving in the same way we do when solving an equation.<\/p>\n<div style=\"text-align: center;\">[latex]\\begin{array}{ll}-\\frac{3}{4}x\\ge -\\frac{5}{8}+\\frac{2}{3}x\\hfill & \\hfill \\\\ -\\frac{3}{4}x-\\frac{2}{3}x\\ge -\\frac{5}{8}\\hfill & \\text{Put variable terms on one side}.\\hfill \\\\ -\\frac{9}{12}x-\\frac{8}{12}x\\ge -\\frac{5}{8}\\hfill & \\text{Write fractions with common denominator}.\\hfill \\\\ -\\frac{17}{12}x\\ge -\\frac{5}{8}\\hfill & \\hfill \\\\ x\\le -\\frac{5}{8}\\left(-\\frac{12}{17}\\right)\\hfill & \\text{Multiplying by a negative number reverses the inequality}.\\hfill \\\\ x\\le \\frac{15}{34}\\hfill & \\hfill \\end{array}[\/latex]<\/div>\n<p>The solution set is the interval [latex]\\left(-\\infty ,\\frac{15}{34}\\right][\/latex].<\/p>\n<\/div>\n<\/div>\n<\/div>\n<div class=\"textbox key-takeaways\">\n<h3>Try It<\/h3>\n<p>Solve the inequality and write the answer in interval notation: [latex]-\\frac{5}{6}x\\le \\frac{3}{4}+\\frac{8}{3}x[\/latex].<\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q524889\">Show Solution<\/span><\/p>\n<div id=\"q524889\" class=\"hidden-answer\" style=\"display: none\">\n<p>[latex]\\left[-\\frac{3}{14},\\infty \\right)[\/latex]<\/p>\n<\/div>\n<\/div>\n<p><iframe loading=\"lazy\" id=\"ohm72891\" class=\"resizable\" src=\"https:\/\/ohm.lumenlearning.com\/multiembedq.php?id=72891&theme=oea&iframe_resize_id=ohm72891&show_question_numbers\" width=\"100%\" height=\"340\"><\/iframe><\/p>\n<\/div>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-111\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Original<\/div><ul class=\"citation-list\"><li>Revision and Adaptation. <strong>Provided by<\/strong>: Lumen Learning. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em><\/li><li>Graphing Inequalities. <strong>Authored by<\/strong>: Lumen Learning. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"https:\/\/www.desmos.com\/calculator\/4529rytfef\">https:\/\/www.desmos.com\/calculator\/4529rytfef<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em><\/li><\/ul><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>College Algebra. <strong>Authored by<\/strong>: Abramson, Jay et al.. <strong>Provided by<\/strong>: OpenStax. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/cnx.org\/contents\/9b08c294-057f-4201-9f48-5d6ad992740d@5.2\">http:\/\/cnx.org\/contents\/9b08c294-057f-4201-9f48-5d6ad992740d@5.2<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em>. <strong>License Terms<\/strong>: Download for free at http:\/\/cnx.org\/contents\/9b08c294-057f-4201-9f48-5d6ad992740d@5.2<\/li><li>Question ID 92604, 92605, 92606, 92607. <strong>Authored by<\/strong>: Michael Jenck. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em>. <strong>License Terms<\/strong>: IMathAS Community License CC-BY + GPL<\/li><li>Question ID 72891. <strong>Authored by<\/strong>: Alyson Day. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em>. <strong>License Terms<\/strong>: IMathAS Community License CC-BY + GPL<\/li><li>Question ID 58. <strong>Authored by<\/strong>: Lippman, David. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em>. <strong>License Terms<\/strong>: IMathAS Community License CC-BY + GPL<\/li><li>Ex: Solving One Step Inequalities by Adding and Subtracting (Variable Left Side). <strong>Authored by<\/strong>: James Sousa (Mathispower4u.com) for Lumen Learning. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"https:\/\/youtu.be\/1Z22Xh66VFM\">https:\/\/youtu.be\/1Z22Xh66VFM<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em><\/li><li>Ex: Solving One Step Inequalities by Adding and Subtracting (Variable Right Side). <strong>Authored by<\/strong>: James Sousa (Mathispower4u.com) for Lumen Learning. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"https:\/\/youtu.be\/RBonYKvTCLU\">https:\/\/youtu.be\/RBonYKvTCLU<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em><\/li><\/ul><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Specific attribution<\/div><ul class=\"citation-list\"><li>College Algebra. <strong>Authored by<\/strong>: OpenStax College Algebra. <strong>Provided by<\/strong>: OpenStax. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/cnx.org\/contents\/9b08c294-057f-4201-9f48-5d6ad992740d@3.278:1\/Preface\">http:\/\/cnx.org\/contents\/9b08c294-057f-4201-9f48-5d6ad992740d@3.278:1\/Preface<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em><\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":395986,"menu_order":26,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc-attribution\",\"description\":\"College Algebra\",\"author\":\"OpenStax College Algebra\",\"organization\":\"OpenStax\",\"url\":\"http:\/\/cnx.org\/contents\/9b08c294-057f-4201-9f48-5d6ad992740d@3.278:1\/Preface\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"\"},{\"type\":\"original\",\"description\":\"Revision and Adaptation\",\"author\":\"\",\"organization\":\"Lumen Learning\",\"url\":\"\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"\"},{\"type\":\"cc\",\"description\":\"College Algebra\",\"author\":\"Abramson, Jay et 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GPL\"},{\"type\":\"cc\",\"description\":\"Question ID 58\",\"author\":\"Lippman, David\",\"organization\":\"\",\"url\":\"\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"IMathAS Community License CC-BY + GPL\"},{\"type\":\"cc\",\"description\":\"Ex: Solving One Step Inequalities by Adding and Subtracting (Variable Left Side)\",\"author\":\"James Sousa (Mathispower4u.com) for Lumen Learning\",\"organization\":\"\",\"url\":\"https:\/\/youtu.be\/1Z22Xh66VFM\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"\"},{\"type\":\"cc\",\"description\":\"Ex: Solving One Step Inequalities by Adding and Subtracting (Variable Right Side)\",\"author\":\"James Sousa (Mathispower4u.com) for Lumen 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