{"id":16300,"date":"2019-10-03T03:06:06","date_gmt":"2019-10-03T03:06:06","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/wm-developmentalemporium\/chapter\/5-1-1-greatest-common-factor\/"},"modified":"2020-10-22T09:31:06","modified_gmt":"2020-10-22T09:31:06","slug":"5-1-1-greatest-common-factor","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/suny-rockland-developmentalemporium\/chapter\/5-1-1-greatest-common-factor\/","title":{"raw":"13.1.a - The Zero Product Principle","rendered":"13.1.a &#8211; The Zero Product Principle"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n<h3>Learning Outcomes<\/h3>\r\n<ul>\r\n \t<li>Use the principle of zero products to solve equations<\/li>\r\n<\/ul>\r\n<\/div>\r\nRecall the profit equation for a cell phone manufacturer from the module on polynomials:\r\n<p style=\"text-align: center\">[latex]P=-0.09x^2+5000x-750,000[\/latex]<\/p>\r\n<p style=\"text-align: left\">Using an online graphing calculator, we can generate this graph of the profit equation.<\/p>\r\n<img class=\" wp-image-4678 aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/117\/2016\/06\/07214325\/Screen-Shot-2016-06-07-at-2.42.59-PM-300x256.png\" alt=\"Screen Shot 2016-06-07 at 2.42.59 PM\" width=\"663\" height=\"566\" \/>\r\n\r\nA manager may want to know for what amount of phones manufactured and sold will a profit be made. \u00a0By substituting [latex]100[\/latex] in for [latex]x[\/latex], we discovered that when [latex]100[\/latex] phones were manufactured and sold, the company did not make a profit.\r\n\r\nSubstitute x = [latex]100[\/latex]\r\n<p style=\"text-align: center\">[latex]\\begin{array}{c}P=-0.09x^2+5000x-750,000\\\\=-0.09\\left(100\\right)^2+5000\\left(100\\right)-750,000\\\\=-900+500,000-750,000\\\\=-250,900\\end{array}[\/latex]<\/p>\r\n<p style=\"text-align: left\">Finding the points where profit is greater than or equal to zero will guide management decisions, and help the company plan to have enough labor and materials on hand. Knowing where profit equals zero gives the company a baseline from which to plan. On the graph, profit is zero when the parabola crosses the x-axis. In algebraic\u00a0terms, this means finding where the profit equation is equal to zero:<\/p>\r\n<p style=\"text-align: center\">[latex]\\begin{array}{c}P=-0.09x^2+5000x-750,000\\\\0=-0.09x^2+5000x-750,000\\\\0&lt;-0.09x^2+5000x-750,000\\end{array}[\/latex]<\/p>\r\n<p style=\"text-align: left\">We know how to solve linear equations like this: [latex]x-4=0[\/latex], and linear inequalities like this: [latex]x-4&gt;0[\/latex]. \u00a0But, how do you solve a polynomial equation like this: [latex]0=-0.09x^2+5000x-750,000[\/latex], or an inequality like this:\u00a0[latex]0&lt;-0.09x^2+5000x-750,000[\/latex]?<\/p>\r\n<p style=\"text-align: left\">In this section we will learn some very useful tools for solving certain kinds of polynomial equations, and in later math courses you will likely learn how to extend these ideas to solving polynomial inequalities. The first concept we will explore is that of the zero product property, then we will discuss how that can be used to solve polynomial equations.<\/p>\r\n\r\n<h2>The Principle of Zero Products<\/h2>\r\n[caption id=\"attachment_4778\" align=\"alignleft\" width=\"104\"]<img class=\" wp-image-4778\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/117\/2016\/06\/10170452\/Screen-Shot-2016-06-10-at-10.04.31-AM-172x300.png\" alt=\"The number zero\" width=\"104\" height=\"181\" \/> Zero[\/caption]\r\n\r\nWhat if we told you that we multiplied two numbers together and got an answer of zero? What could you say about the two numbers? Could they be [latex]2[\/latex] and \u00a0[latex]5[\/latex]? Could they be [latex]9[\/latex] and [latex]1[\/latex]? No! When the result (answer) from multiplying two numbers is zero, that means that one of them\u00a0<em>had\u00a0<\/em>to be zero. This idea is called the zero product principle, and it is useful for solving certain kinds of equations, like we described in the cell phone manufacturer example.\r\n\r\n&nbsp;\r\n<div class=\"textbox shaded\">\r\n<h3>Principle of Zero Products<\/h3>\r\nThe Principle of Zero Products states that if the product of two numbers is [latex]0[\/latex], then at least one of the factors is [latex]0[\/latex].\u00a0If [latex]ab=0[\/latex], then either [latex]a=0[\/latex] or [latex]b=0[\/latex], or both <em>a<\/em> and <em>b<\/em> are \u00a0[latex]0[\/latex].\r\n\r\n<\/div>\r\n&nbsp;\r\n<div class=\"textbox exercises\">\r\n<h3>Example<\/h3>\r\nUse the principle of zero products to solve. [latex]5y=0[\/latex]\r\n[reveal-answer q=\"547123\"]Show Solution[\/reveal-answer]\r\n[hidden-answer a=\"547123\"]\r\n\r\nBy the principle of zero products, when two factors are multiplied and the result is zero at least one of them is equal to zero. \u00a0Therefore, either [latex]5=0[\/latex], or [latex]y=0[\/latex].\r\n\r\nIn this case, we know that [latex]5[\/latex] is not equal to zero, so [latex]y[\/latex] must be equal to zero.\r\n\r\nWe can verify this with algebra.\r\n<p style=\"text-align: center\">[latex]\\begin{array}{c}5y=0\\\\\\text{}\\\\\\frac{5y}{5}=\\frac{0}{5}\\\\\\text{}\\\\y=0\\end{array}[\/latex]<\/p>\r\n\r\n<h4 style=\"text-align: left\">Answer<\/h4>\r\nBoth by the principle of \u00a0zero products, and with algebra, we have shown that [latex]y=0[\/latex].\r\n\r\n[\/hidden-answer]\r\n\r\n<\/div>\r\nWe can extend this idea to products of more than just two numbers. \u00a0In the next example we will show that we can use the principle of zero products to solve an equation containing the product of a number and a binomial.\r\n<div class=\"textbox exercises\">\r\n<h3>Example<\/h3>\r\nUse the principle of zero products to solve:\r\n\r\n[latex]7\\left(y-2\\right)=0[\/latex]\r\n[reveal-answer q=\"726832\"]Show Solution[\/reveal-answer]\r\n[hidden-answer a=\"726832\"]\r\n\r\nBy the principle of zero products, either [latex]7 = 0[\/latex], or\u00a0[latex]\\left(y-2\\right)=0[\/latex]. \u00a0We know that [latex]7\\neq0[\/latex], so we are left with\u00a0[latex]\\left(y-2\\right)=0[\/latex]. \u00a0We know how to solve this kind of equation!\r\n\r\nWe can remove the parentheses because they are not needed to solve.\r\n<p style=\"text-align: center\">[latex]\\begin{array}{c}y-2=0\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\underline{+2}\\,\\,\\,\\,\\,\\,\\underline{+2}\\\\\\text{}\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,y=2\\end{array}[\/latex]<\/p>\r\n<p style=\"text-align: left\">We can check this is correct by substituting [latex]2[\/latex] for y into the original equation.<\/p>\r\n<p style=\"text-align: center\">[latex]\\begin{array}{c}7\\left(2-2\\right)=0\\\\7\\left(0\\right)=0\\\\0=0\\end{array}[\/latex]<\/p>\r\n<p style=\"text-align: left\">This statement is true, so we have found the correct value for [latex]y[\/latex].<\/p>\r\n\r\n<h4 style=\"text-align: left\">Answer<\/h4>\r\n<p style=\"text-align: left\">[latex]y=2[\/latex]<\/p>\r\n[\/hidden-answer]\r\n\r\n<\/div>\r\nWe could have used the distributive property and the addition and multiplication properties of equality to solve the equation in the previous example. It would look something like this:\r\n\r\nSolve\u00a0[latex]7\\left(y-2\\right)=0[\/latex] using the distributive property.\r\n<p style=\"text-align: center\">[latex]\\begin{array}{c}7\\left(y-2\\right)=0\\\\7y-14=0\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\underline{+14}\\,\\,\\,\\,\\,\\,\\underline{+14}\\\\\\text{}\\\\7y=14\\\\\\text{}\\\\\\frac{7y}{7}=\\frac{14}{7}\\\\\\text{}\\\\y=2\\end{array}[\/latex]<\/p>\r\n<p style=\"text-align: left\">We have the same answer that we verified in the example, but we used different algebraic principles to find it.<\/p>\r\nIn the next example we add another layer to the idea that we can use the principle of zero products to solve equations. We will solve an equation that contains the product of a variable and a binomial.\r\n<div class=\"textbox exercises\">\r\n<h3>Example<\/h3>\r\nUse the\u00a0principle of zero products to solve:\r\n\r\n[latex]t\\left(5-t\\right)=0[\/latex]\r\n\r\n[reveal-answer q=\"649695\"]Show Solution[\/reveal-answer]\r\n[hidden-answer a=\"649695\"]\r\n\r\nBy the principle of zero products, either [latex]t=0[\/latex] or [latex]\\left(5-t\\right)=0[\/latex]\r\n\r\n[latex]\\displaystyle\\begin{array}{c}t=0\\,\\,\\,\\,\\,\\,\\,\\,\\,\\text{OR}\\,\\,\\,\\,\\,\\,\\,\\,5-t=0\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\underline{-5}\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\underline{-5}\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,-t=-5\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\frac{-t}{-1}=\\frac{-5}{-1}\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,t=5\\\\\\text{}\\\\t=0\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\text{OR}\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,t=5\\end{array}[\/latex]\r\n\r\nWow, two answers! \u00a0Let's check that they are both correct.\r\n\r\nSubstitute\u00a0[latex]t=0[\/latex]\r\n<p style=\"text-align: center\">[latex]\\begin{array}{c}t\\left(5-t\\right)=0\\\\0\\left(5-0\\right)=0\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,0\\left(5\\right)=0\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,0=0\\end{array}[\/latex]<\/p>\r\n[latex]t=0[\/latex] checks, now let's check [latex]t=5[\/latex]\r\n\r\nSubstitute [latex]t=5[\/latex]\r\n<p style=\"text-align: center\">[latex]\\begin{array}{c}5\\left(5-5\\right)=0\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,5\\left(0\\right)=0\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,0=0\\end{array}[\/latex]<\/p>\r\n\u00a0[latex]t=5[\/latex] also checks. \u00a0There are two answers to this equation.\r\n<h4>Answer<\/h4>\r\n[latex]t=0\\text{ OR }t=5[\/latex]\r\n\r\n[\/hidden-answer]\r\n\r\n<\/div>\r\nWhy don't we just use the distributive property to solve these kind of equations? Let's try using the distributive property on the previous example to explain why this will not always work.\r\n<p style=\"text-align: center\">[latex]\\begin{array}{c}t\\left(5-t\\right)=0\\\\\\text{}\\\\5t-t^2=0\\\\\\underline{-5t}\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\underline{-5t}\\\\t^2=-5t\\\\\\text{}\\\\t\\cdot{t}=-5t\\\\\\text{}\\\\\\frac{t\\cdot{t}}{t}=\\frac{-5t}{t}\\\\\\text{}\\\\t=-5\\end{array}[\/latex]<\/p>\r\nWait, in the example, our solution was\u00a0[latex]t=0\\text{ OR }t=5[\/latex]. \u00a0Let's check this new answer to see if it is correct.\r\n\r\nSubstitute [latex]t=-5[\/latex]\r\n<p style=\"text-align: center\">[latex]\\begin{array}{c}-5\\left(5-\\left(-5\\right)\\right)=0\\\\-5\\left(5+5\\right)=0\\\\-5\\left(10\\right)=0\\\\-50\\neq{0}\\end{array}[\/latex]<\/p>\r\n<p style=\"text-align: left\">This isn't even the right answer!<\/p>\r\n<p style=\"text-align: left\">When we are solving polynomial equations, we need to use some different\u00a0methods than we used to solve linear equations to make sure we get <em>all<\/em> of the<em> correct<\/em> answers. \u00a0The principle of zero products is one tool that allows us to do this.<\/p>\r\n\r\n<div class=\"textbox shaded\">\r\n\r\n<img class=\" wp-image-2132 alignleft\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/1468\/2016\/03\/22011815\/traffic-sign-160659-300x265.png\" alt=\"Caution\" width=\"65\" height=\"57\" \/>Caution! \u00a0It is important to remember that the principle of zero products <strong>only<\/strong> works when we have an equation with zero on one side, and only a product on the other side. The table below gives examples of equations for which you can and cannot apply the principle of zero products.\r\n<table>\r\n<thead>\r\n<tr>\r\n<td>YES Zero Products Works to Solve<\/td>\r\n<td>NO Zero Products Does Not Work to Solve<\/td>\r\n<td>WHY NOT?<\/td>\r\n<\/tr>\r\n<\/thead>\r\n<tbody>\r\n<tr>\r\n<td>[latex]\\frac{1}{2}\\left(x-2\\right)=0[\/latex]<\/td>\r\n<td>[latex]\\frac{1}{2}\\left(x-2\\right)=28[\/latex]<\/td>\r\n<td>There is\u00a0a product on the left, but it is not equal to zero.<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>[latex]s\\left(9+s\\right)=0[\/latex]<\/td>\r\n<td>[latex]s^2+9=0[\/latex]<\/td>\r\n<td>There is a sum equal to zero but no product equal to zero.<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<\/div>\r\nLet's look at one more example of how the\u00a0principle of zero products can be used to solve equations involving products that are binomials.\r\n<div class=\"textbox exercises\">\r\n<h3>Example<\/h3>\r\nUse the\u00a0principle of zero products to solve:\r\n\r\n[latex]\\left(s+1\\right)\\left(s-5\\right)=0[\/latex]\r\n[reveal-answer q=\"499648\"]Show Solution[\/reveal-answer]\r\n[hidden-answer a=\"499648\"]\r\n\r\nSet both products equal to zero, then solve the linear equations.\r\n\r\n[latex]\\begin{array}{c}\\left(s+1\\right)=0\\\\s+1=0\\\\\\underline{-1}\\,\\,\\,\\,\\,\\,\\,\\underline{-1}\\\\s=-1\\end{array}[\/latex]\r\n\r\n[latex]\\begin{array}{c}\\left(s-5\\right)=0\\\\s-5=0\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\underline{+5}\\,\\,\\,\\,\\,\\underline{+5}\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,s=5\\end{array}[\/latex]\r\n<h4>Answer<\/h4>\r\n[latex]s=-1\\text{ OR }s=5[\/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\n[ohm_question]126906[\/ohm_question]\r\n\r\n<\/div>\r\nThe last two examples we showed were both polynomial equations that were degree two. Remember that degree means the largest exponent in the polynomial. Degree two polynomials are often called quadratic. \u00a0Using the distributive property to multiply the products in the last example will help you see that it is a degree two polynomial.\r\n\r\nUse a table:\r\n<table style=\"width: 20%\">\r\n<tbody>\r\n<tr>\r\n<td><\/td>\r\n<td>[latex]s[\/latex]<\/td>\r\n<td>[latex]+1[\/latex]<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>[latex]s[\/latex]<\/td>\r\n<td>[latex]s^2[\/latex]<\/td>\r\n<td>[latex]s[\/latex]<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>[latex]-5[\/latex]<\/td>\r\n<td>[latex]-5s[\/latex]<\/td>\r\n<td>\u00a0[latex]-5[\/latex]<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\nCombine terms and simplify:\r\n\r\n[latex]\\begin{array}{c}s^2+s-5s-5\\\\=s^2-4s-5\\end{array}[\/latex]\r\n\r\nWhen the polynomial is simplified, you can tell that it is a degree two polynomial, or a quadratic polynomial. At the start of this page, we proposed that a business would be interested in where the quadratic polynomial that represented profit was equal to or greater than zero. \u00a0We have presented one way to find where a quadratic polynomial is equal to zero, as long as it is in the form of a product of two binomials, and hasn't been multiplied out.\r\n\r\nIn the following video we present more examples of how to use the zero product principle to solve polynomial equations that are in factored form.\r\n\r\nhttps:\/\/youtu.be\/yCcMCPHFrVc\r\n\r\nWhat would you do if you were asked to solve\u00a0a quadratic equation\u00a0such as [latex]y^2+2y=0[\/latex]? We have already shown that we can't use the same techniques we used to solve linear equations. \u00a0In the next section, we will show you how to re-write\u00a0[latex]y^2+2y=0[\/latex] as the product of a monomial and a binomial\u00a0so you can use the zero product principle to solve it.","rendered":"<div class=\"textbox learning-objectives\">\n<h3>Learning Outcomes<\/h3>\n<ul>\n<li>Use the principle of zero products to solve equations<\/li>\n<\/ul>\n<\/div>\n<p>Recall the profit equation for a cell phone manufacturer from the module on polynomials:<\/p>\n<p style=\"text-align: center\">[latex]P=-0.09x^2+5000x-750,000[\/latex]<\/p>\n<p style=\"text-align: left\">Using an online graphing calculator, we can generate this graph of the profit equation.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-4678 aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/117\/2016\/06\/07214325\/Screen-Shot-2016-06-07-at-2.42.59-PM-300x256.png\" alt=\"Screen Shot 2016-06-07 at 2.42.59 PM\" width=\"663\" height=\"566\" \/><\/p>\n<p>A manager may want to know for what amount of phones manufactured and sold will a profit be made. \u00a0By substituting [latex]100[\/latex] in for [latex]x[\/latex], we discovered that when [latex]100[\/latex] phones were manufactured and sold, the company did not make a profit.<\/p>\n<p>Substitute x = [latex]100[\/latex]<\/p>\n<p style=\"text-align: center\">[latex]\\begin{array}{c}P=-0.09x^2+5000x-750,000\\\\=-0.09\\left(100\\right)^2+5000\\left(100\\right)-750,000\\\\=-900+500,000-750,000\\\\=-250,900\\end{array}[\/latex]<\/p>\n<p style=\"text-align: left\">Finding the points where profit is greater than or equal to zero will guide management decisions, and help the company plan to have enough labor and materials on hand. Knowing where profit equals zero gives the company a baseline from which to plan. On the graph, profit is zero when the parabola crosses the x-axis. In algebraic\u00a0terms, this means finding where the profit equation is equal to zero:<\/p>\n<p style=\"text-align: center\">[latex]\\begin{array}{c}P=-0.09x^2+5000x-750,000\\\\0=-0.09x^2+5000x-750,000\\\\0<-0.09x^2+5000x-750,000\\end{array}[\/latex]<\/p>\n<p style=\"text-align: left\">We know how to solve linear equations like this: [latex]x-4=0[\/latex], and linear inequalities like this: [latex]x-4>0[\/latex]. \u00a0But, how do you solve a polynomial equation like this: [latex]0=-0.09x^2+5000x-750,000[\/latex], or an inequality like this:\u00a0[latex]0<-0.09x^2+5000x-750,000[\/latex]?<\/p>\n<p style=\"text-align: left\">In this section we will learn some very useful tools for solving certain kinds of polynomial equations, and in later math courses you will likely learn how to extend these ideas to solving polynomial inequalities. The first concept we will explore is that of the zero product property, then we will discuss how that can be used to solve polynomial equations.<\/p>\n<h2>The Principle of Zero Products<\/h2>\n<div id=\"attachment_4778\" style=\"width: 114px\" class=\"wp-caption alignleft\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-4778\" class=\"wp-image-4778\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/117\/2016\/06\/10170452\/Screen-Shot-2016-06-10-at-10.04.31-AM-172x300.png\" alt=\"The number zero\" width=\"104\" height=\"181\" \/><\/p>\n<p id=\"caption-attachment-4778\" class=\"wp-caption-text\">Zero<\/p>\n<\/div>\n<p>What if we told you that we multiplied two numbers together and got an answer of zero? What could you say about the two numbers? Could they be [latex]2[\/latex] and \u00a0[latex]5[\/latex]? Could they be [latex]9[\/latex] and [latex]1[\/latex]? No! When the result (answer) from multiplying two numbers is zero, that means that one of them\u00a0<em>had\u00a0<\/em>to be zero. This idea is called the zero product principle, and it is useful for solving certain kinds of equations, like we described in the cell phone manufacturer example.<\/p>\n<p>&nbsp;<\/p>\n<div class=\"textbox shaded\">\n<h3>Principle of Zero Products<\/h3>\n<p>The Principle of Zero Products states that if the product of two numbers is [latex]0[\/latex], then at least one of the factors is [latex]0[\/latex].\u00a0If [latex]ab=0[\/latex], then either [latex]a=0[\/latex] or [latex]b=0[\/latex], or both <em>a<\/em> and <em>b<\/em> are \u00a0[latex]0[\/latex].<\/p>\n<\/div>\n<p>&nbsp;<\/p>\n<div class=\"textbox exercises\">\n<h3>Example<\/h3>\n<p>Use the principle of zero products to solve. [latex]5y=0[\/latex]<\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q547123\">Show Solution<\/span><\/p>\n<div id=\"q547123\" class=\"hidden-answer\" style=\"display: none\">\n<p>By the principle of zero products, when two factors are multiplied and the result is zero at least one of them is equal to zero. \u00a0Therefore, either [latex]5=0[\/latex], or [latex]y=0[\/latex].<\/p>\n<p>In this case, we know that [latex]5[\/latex] is not equal to zero, so [latex]y[\/latex] must be equal to zero.<\/p>\n<p>We can verify this with algebra.<\/p>\n<p style=\"text-align: center\">[latex]\\begin{array}{c}5y=0\\\\\\text{}\\\\\\frac{5y}{5}=\\frac{0}{5}\\\\\\text{}\\\\y=0\\end{array}[\/latex]<\/p>\n<h4 style=\"text-align: left\">Answer<\/h4>\n<p>Both by the principle of \u00a0zero products, and with algebra, we have shown that [latex]y=0[\/latex].<\/p>\n<\/div>\n<\/div>\n<\/div>\n<p>We can extend this idea to products of more than just two numbers. \u00a0In the next example we will show that we can use the principle of zero products to solve an equation containing the product of a number and a binomial.<\/p>\n<div class=\"textbox exercises\">\n<h3>Example<\/h3>\n<p>Use the principle of zero products to solve:<\/p>\n<p>[latex]7\\left(y-2\\right)=0[\/latex]<\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q726832\">Show Solution<\/span><\/p>\n<div id=\"q726832\" class=\"hidden-answer\" style=\"display: none\">\n<p>By the principle of zero products, either [latex]7 = 0[\/latex], or\u00a0[latex]\\left(y-2\\right)=0[\/latex]. \u00a0We know that [latex]7\\neq0[\/latex], so we are left with\u00a0[latex]\\left(y-2\\right)=0[\/latex]. \u00a0We know how to solve this kind of equation!<\/p>\n<p>We can remove the parentheses because they are not needed to solve.<\/p>\n<p style=\"text-align: center\">[latex]\\begin{array}{c}y-2=0\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\underline{+2}\\,\\,\\,\\,\\,\\,\\underline{+2}\\\\\\text{}\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,y=2\\end{array}[\/latex]<\/p>\n<p style=\"text-align: left\">We can check this is correct by substituting [latex]2[\/latex] for y into the original equation.<\/p>\n<p style=\"text-align: center\">[latex]\\begin{array}{c}7\\left(2-2\\right)=0\\\\7\\left(0\\right)=0\\\\0=0\\end{array}[\/latex]<\/p>\n<p style=\"text-align: left\">This statement is true, so we have found the correct value for [latex]y[\/latex].<\/p>\n<h4 style=\"text-align: left\">Answer<\/h4>\n<p style=\"text-align: left\">[latex]y=2[\/latex]<\/p>\n<\/div>\n<\/div>\n<\/div>\n<p>We could have used the distributive property and the addition and multiplication properties of equality to solve the equation in the previous example. It would look something like this:<\/p>\n<p>Solve\u00a0[latex]7\\left(y-2\\right)=0[\/latex] using the distributive property.<\/p>\n<p style=\"text-align: center\">[latex]\\begin{array}{c}7\\left(y-2\\right)=0\\\\7y-14=0\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\underline{+14}\\,\\,\\,\\,\\,\\,\\underline{+14}\\\\\\text{}\\\\7y=14\\\\\\text{}\\\\\\frac{7y}{7}=\\frac{14}{7}\\\\\\text{}\\\\y=2\\end{array}[\/latex]<\/p>\n<p style=\"text-align: left\">We have the same answer that we verified in the example, but we used different algebraic principles to find it.<\/p>\n<p>In the next example we add another layer to the idea that we can use the principle of zero products to solve equations. We will solve an equation that contains the product of a variable and a binomial.<\/p>\n<div class=\"textbox exercises\">\n<h3>Example<\/h3>\n<p>Use the\u00a0principle of zero products to solve:<\/p>\n<p>[latex]t\\left(5-t\\right)=0[\/latex]<\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q649695\">Show Solution<\/span><\/p>\n<div id=\"q649695\" class=\"hidden-answer\" style=\"display: none\">\n<p>By the principle of zero products, either [latex]t=0[\/latex] or [latex]\\left(5-t\\right)=0[\/latex]<\/p>\n<p>[latex]\\displaystyle\\begin{array}{c}t=0\\,\\,\\,\\,\\,\\,\\,\\,\\,\\text{OR}\\,\\,\\,\\,\\,\\,\\,\\,5-t=0\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\underline{-5}\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\underline{-5}\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,-t=-5\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\frac{-t}{-1}=\\frac{-5}{-1}\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,t=5\\\\\\text{}\\\\t=0\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\text{OR}\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,t=5\\end{array}[\/latex]<\/p>\n<p>Wow, two answers! \u00a0Let&#8217;s check that they are both correct.<\/p>\n<p>Substitute\u00a0[latex]t=0[\/latex]<\/p>\n<p style=\"text-align: center\">[latex]\\begin{array}{c}t\\left(5-t\\right)=0\\\\0\\left(5-0\\right)=0\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,0\\left(5\\right)=0\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,0=0\\end{array}[\/latex]<\/p>\n<p>[latex]t=0[\/latex] checks, now let&#8217;s check [latex]t=5[\/latex]<\/p>\n<p>Substitute [latex]t=5[\/latex]<\/p>\n<p style=\"text-align: center\">[latex]\\begin{array}{c}5\\left(5-5\\right)=0\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,5\\left(0\\right)=0\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,0=0\\end{array}[\/latex]<\/p>\n<p>\u00a0[latex]t=5[\/latex] also checks. \u00a0There are two answers to this equation.<\/p>\n<h4>Answer<\/h4>\n<p>[latex]t=0\\text{ OR }t=5[\/latex]<\/p>\n<\/div>\n<\/div>\n<\/div>\n<p>Why don&#8217;t we just use the distributive property to solve these kind of equations? Let&#8217;s try using the distributive property on the previous example to explain why this will not always work.<\/p>\n<p style=\"text-align: center\">[latex]\\begin{array}{c}t\\left(5-t\\right)=0\\\\\\text{}\\\\5t-t^2=0\\\\\\underline{-5t}\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\underline{-5t}\\\\t^2=-5t\\\\\\text{}\\\\t\\cdot{t}=-5t\\\\\\text{}\\\\\\frac{t\\cdot{t}}{t}=\\frac{-5t}{t}\\\\\\text{}\\\\t=-5\\end{array}[\/latex]<\/p>\n<p>Wait, in the example, our solution was\u00a0[latex]t=0\\text{ OR }t=5[\/latex]. \u00a0Let&#8217;s check this new answer to see if it is correct.<\/p>\n<p>Substitute [latex]t=-5[\/latex]<\/p>\n<p style=\"text-align: center\">[latex]\\begin{array}{c}-5\\left(5-\\left(-5\\right)\\right)=0\\\\-5\\left(5+5\\right)=0\\\\-5\\left(10\\right)=0\\\\-50\\neq{0}\\end{array}[\/latex]<\/p>\n<p style=\"text-align: left\">This isn&#8217;t even the right answer!<\/p>\n<p style=\"text-align: left\">When we are solving polynomial equations, we need to use some different\u00a0methods than we used to solve linear equations to make sure we get <em>all<\/em> of the<em> correct<\/em> answers. \u00a0The principle of zero products is one tool that allows us to do this.<\/p>\n<div class=\"textbox shaded\">\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-2132 alignleft\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/1468\/2016\/03\/22011815\/traffic-sign-160659-300x265.png\" alt=\"Caution\" width=\"65\" height=\"57\" \/>Caution! \u00a0It is important to remember that the principle of zero products <strong>only<\/strong> works when we have an equation with zero on one side, and only a product on the other side. The table below gives examples of equations for which you can and cannot apply the principle of zero products.<\/p>\n<table>\n<thead>\n<tr>\n<td>YES Zero Products Works to Solve<\/td>\n<td>NO Zero Products Does Not Work to Solve<\/td>\n<td>WHY NOT?<\/td>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>[latex]\\frac{1}{2}\\left(x-2\\right)=0[\/latex]<\/td>\n<td>[latex]\\frac{1}{2}\\left(x-2\\right)=28[\/latex]<\/td>\n<td>There is\u00a0a product on the left, but it is not equal to zero.<\/td>\n<\/tr>\n<tr>\n<td>[latex]s\\left(9+s\\right)=0[\/latex]<\/td>\n<td>[latex]s^2+9=0[\/latex]<\/td>\n<td>There is a sum equal to zero but no product equal to zero.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>Let&#8217;s look at one more example of how the\u00a0principle of zero products can be used to solve equations involving products that are binomials.<\/p>\n<div class=\"textbox exercises\">\n<h3>Example<\/h3>\n<p>Use the\u00a0principle of zero products to solve:<\/p>\n<p>[latex]\\left(s+1\\right)\\left(s-5\\right)=0[\/latex]<\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q499648\">Show Solution<\/span><\/p>\n<div id=\"q499648\" class=\"hidden-answer\" style=\"display: none\">\n<p>Set both products equal to zero, then solve the linear equations.<\/p>\n<p>[latex]\\begin{array}{c}\\left(s+1\\right)=0\\\\s+1=0\\\\\\underline{-1}\\,\\,\\,\\,\\,\\,\\,\\underline{-1}\\\\s=-1\\end{array}[\/latex]<\/p>\n<p>[latex]\\begin{array}{c}\\left(s-5\\right)=0\\\\s-5=0\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\,\\underline{+5}\\,\\,\\,\\,\\,\\underline{+5}\\\\\\,\\,\\,\\,\\,\\,\\,\\,\\,s=5\\end{array}[\/latex]<\/p>\n<h4>Answer<\/h4>\n<p>[latex]s=-1\\text{ OR }s=5[\/latex]<\/p>\n<\/div>\n<\/div>\n<\/div>\n<div class=\"textbox key-takeaways\">\n<h3>Try It<\/h3>\n<p><iframe loading=\"lazy\" id=\"ohm126906\" class=\"resizable\" src=\"https:\/\/ohm.lumenlearning.com\/multiembedq.php?id=126906&theme=oea&iframe_resize_id=ohm126906&show_question_numbers\" width=\"100%\" height=\"150\"><\/iframe><\/p>\n<\/div>\n<p>The last two examples we showed were both polynomial equations that were degree two. Remember that degree means the largest exponent in the polynomial. Degree two polynomials are often called quadratic. \u00a0Using the distributive property to multiply the products in the last example will help you see that it is a degree two polynomial.<\/p>\n<p>Use a table:<\/p>\n<table style=\"width: 20%\">\n<tbody>\n<tr>\n<td><\/td>\n<td>[latex]s[\/latex]<\/td>\n<td>[latex]+1[\/latex]<\/td>\n<\/tr>\n<tr>\n<td>[latex]s[\/latex]<\/td>\n<td>[latex]s^2[\/latex]<\/td>\n<td>[latex]s[\/latex]<\/td>\n<\/tr>\n<tr>\n<td>[latex]-5[\/latex]<\/td>\n<td>[latex]-5s[\/latex]<\/td>\n<td>\u00a0[latex]-5[\/latex]<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Combine terms and simplify:<\/p>\n<p>[latex]\\begin{array}{c}s^2+s-5s-5\\\\=s^2-4s-5\\end{array}[\/latex]<\/p>\n<p>When the polynomial is simplified, you can tell that it is a degree two polynomial, or a quadratic polynomial. At the start of this page, we proposed that a business would be interested in where the quadratic polynomial that represented profit was equal to or greater than zero. \u00a0We have presented one way to find where a quadratic polynomial is equal to zero, as long as it is in the form of a product of two binomials, and hasn&#8217;t been multiplied out.<\/p>\n<p>In the following video we present more examples of how to use the zero product principle to solve polynomial equations that are in factored form.<\/p>\n<p><iframe loading=\"lazy\" id=\"oembed-1\" title=\"Ex: Solve an Equation in Factored Form\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/yCcMCPHFrVc?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<p>What would you do if you were asked to solve\u00a0a quadratic equation\u00a0such as [latex]y^2+2y=0[\/latex]? We have already shown that we can&#8217;t use the same techniques we used to solve linear equations. \u00a0In the next section, we will show you how to re-write\u00a0[latex]y^2+2y=0[\/latex] as the product of a monomial and a binomial\u00a0so you can use the zero product principle to solve it.<\/p>\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-16300\">\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>Screenshot: Zero. <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>Screenshot: Caution. <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><\/ul><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>Ex: Solve an Equation in Factored Form. <strong>Authored by<\/strong>: James Sousa (Mathispower4u.com) . <strong>Located at<\/strong>: <a target=\"_blank\" href=\"https:\/\/youtu.be\/yCcMCPHFrVc\">https:\/\/youtu.be\/yCcMCPHFrVc<\/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>Unit 12: Factoring, from Developmental Math: An Open Program. <strong>Provided by<\/strong>: Monterey Institute of Technology and Education. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/nrocnetwork.org\/resources\/downloads\/nroc-math-open-textbook-units-1-12-pdf-and-word-formats\/\">http:\/\/nrocnetwork.org\/resources\/downloads\/nroc-math-open-textbook-units-1-12-pdf-and-word-formats\/<\/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":169554,"menu_order":3,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Ex: Solve an Equation in Factored Form\",\"author\":\"James Sousa (Mathispower4u.com) \",\"organization\":\"\",\"url\":\"https:\/\/youtu.be\/yCcMCPHFrVc\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"\"},{\"type\":\"original\",\"description\":\"Revision and Adaptation\",\"author\":\"\",\"organization\":\"Lumen 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