{"id":1219,"date":"2016-10-21T20:54:34","date_gmt":"2016-10-21T20:54:34","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/waymakercollegealgebra\/?post_type=chapter&#038;p=1219"},"modified":"2017-04-03T23:04:51","modified_gmt":"2017-04-03T23:04:51","slug":"why-it-matters-polynomials-and-rational-expressions-2","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/ivytech-wmopen-collegealgebra\/chapter\/why-it-matters-polynomials-and-rational-expressions-2\/","title":{"raw":"Why It Matters: Polynomials and Rational Expressions","rendered":"Why It Matters: Polynomials and Rational Expressions"},"content":{"raw":"[caption id=\"attachment_3620\" align=\"alignright\" width=\"421\"]<img class=\"wp-image-3620\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/896\/2017\/03\/15231638\/dollar-1071788_1920-300x193.jpg\" alt=\"Arrangement of US currency in a circular pattern with a Statue of Liberty dollar coin in the center and one-dollar bills radiating outward from it.\" width=\"421\" height=\"271\" \/> Arrangement of US currency; money serves as a medium of financial exchange in economics.[\/caption]\r\n<h2>What are Polynomials and Rational Expressions Used For?<\/h2>\r\nIn economics we learn that <strong>profit<\/strong> is the difference between <strong>revenue<\/strong> (money coming in), and <strong>costs<\/strong> (money going out). \u00a0Positive profit means that there is a net inflow of money, while negative profit means that money is being lost.\r\n\r\nSuppose that you own a company that manufactures and sells furniture. \u00a0A particular chair sells for $40. If your company builds and sells 500 of these chairs in one month, then your monthly revenue would be $20,000. In general, if you manufacture and sell [latex]x[\/latex] chairs, then the revenue [latex]R[\/latex], in dollars, would be given by this formula:\r\n<p style=\"text-align: center;\">[latex]R=40x[\/latex]<\/p>\r\n&nbsp;\r\n\r\nNow let\u2019s talk about costs. Let\u2019s say it costs $10,000 each month just to keep the factory open, regardless of how many chairs are produced. This amount might include the electric and gas bills as well as the monthly paychecks for each of your employees. These costs, which do not depend on the number of items produced, are called the <strong>overhead<\/strong> costs. Furthermore, suppose the materials cost $25 per chair. That means that if we produced [latex]x[\/latex] chairs, then the total cost for materials would be [latex]$25x[\/latex]. Together with the overhead, we can derive a total estimated cost formula.\r\n<p style=\"text-align: center;\">[latex]C=\\left(overhead\\right)+\\left(materials\\right)=10,000+25x[\/latex]<\/p>\r\n&nbsp;\r\n\r\nBoth formulas for revenue and cost are examples of <strong>polynomials<\/strong>. In fact both polynomials are what we call <strong>degree 1<\/strong>, or <strong>linear<\/strong> polynomials, because the variable [latex]x[\/latex] only occurs with exponent 1. \u00a0What is the profit formula? \u00a0Simply subtract the two expressions \u00a0(Profit = Revenue - Costs), to find:\r\n<p style=\"text-align: center;\">[latex]P=R-C[\/latex]<\/p>\r\n<p style=\"text-align: center;\">[latex]P=\\left(40x\\right)-\\left(10,000+25x\\right)[\/latex]<\/p>\r\n<p style=\"text-align: center;\">[latex]P=40x-10,000-25x[\/latex]<\/p>\r\n<p style=\"text-align: center;\">[latex]P=15x-10,000[\/latex]<\/p>\r\n&nbsp;\r\n\r\nWill your company make money if it manufactures and sells 500 chairs? \u00a0What about 800 chairs?\r\n\r\n<img class=\" wp-image-3671 alignleft\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/896\/2017\/03\/16230558\/40chair-192x300.jpg\" alt=\"Basic wooden chair with the price of $40.\" width=\"193\" height=\"301\" \/>\r\n\r\nNow imagine that your small company has gotten more and more business over that past few months. You\u2019re producing so many chairs that you had to hire new employees, purchase new trucks and even plan for a larger factory. Those costs are adding up!\r\n\r\n&nbsp;\r\n\r\nAfter carefully analyzing monthly expenses, you estimate the additional costs (above and beyond the overhead and materials costs) to be modeled by a <strong>degree 2<\/strong> (or <strong>quadratic<\/strong>) term, [latex]0.001x^2[\/latex]. Here are your new cost and profit formulas:\r\n<p style=\"text-align: center;\">[latex]C=10,000+15x+0.001x^2[\/latex]<\/p>\r\n<p style=\"text-align: center;\">[latex]P=40x-\\left(10,000+25x+0.001x^2\\right)=-0.001x^2+15x-10,000[\/latex]<\/p>\r\n&nbsp;\r\n\r\nThese new formulas are also polynomials, but they behave differently than the previous formulas for large values of [latex]x[\/latex].\r\n\r\n&nbsp;\r\n\r\nFinally, let\u2019s suppose you want to find out whether it is still cost-effective to produce your $40 chairs in mass quantities. Perhaps the best way to find out is to determine the <strong>average profit<\/strong> when [latex]x[\/latex] chairs are manufactured and sold. As always, an average is equal to the total amount ([latex]P[\/latex], for profit in this case) divided by the number of items ([latex]x[\/latex]).\r\n<p style=\"text-align: center;\">[latex]\\Large\\frac{P}{x}=\\frac{-0.001x^2+15x-10,000}{x}[\/latex]<\/p>\r\n&nbsp;\r\n\r\nThis time, the formula for average profit is no longer a polynomial, but a <strong>rational function<\/strong>, which is the ratio of two polynomials.\r\n\r\n&nbsp;\r\n\r\nIn this module, you\u2019ll learn how to classify and perform algebraic operations on polynomials and rational functions. We will check back in on our company\u2019s profits at the end of the module.\r\n<h3><\/h3>\r\n&nbsp;\r\n<div class=\"textbox learning-objectives\">\r\n<h3>Learning Objectives<\/h3>\r\nPolynomial Basics\r\n<ul class=\"ul1\">\r\n \t<li class=\"li2\"><span class=\"s1\">Identify the degree, leading coefficient, and leading term of a polynomial expression<\/span><\/li>\r\n \t<li class=\"li2\"><span class=\"s1\">Perform algebraic operations on polynomial expressions<\/span><\/li>\r\n<\/ul>\r\n<p class=\"p1\"><span class=\"s1\">Factoring Polynomials<\/span><\/p>\r\n\r\n<ul class=\"ul1\">\r\n \t<li class=\"li2\"><span class=\"s1\">Identify the greatest common factor of a polynomial expression<\/span><\/li>\r\n \t<li class=\"li2\"><span class=\"s1\">Factor a wide variety of polynomials including those with fractional or negative exponents<\/span><\/li>\r\n<\/ul>\r\n<p class=\"p1\"><span class=\"s1\">Rational Expressions<\/span><\/p>\r\n\r\n<ul class=\"ul1\">\r\n \t<li class=\"li3\"><span class=\"s5\">Simplify and perform algebraic operations on rational expressions<\/span><\/li>\r\n<\/ul>\r\n<\/div>\r\n&nbsp;","rendered":"<div id=\"attachment_3620\" style=\"width: 431px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-3620\" class=\"wp-image-3620\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/896\/2017\/03\/15231638\/dollar-1071788_1920-300x193.jpg\" alt=\"Arrangement of US currency in a circular pattern with a Statue of Liberty dollar coin in the center and one-dollar bills radiating outward from it.\" width=\"421\" height=\"271\" \/><\/p>\n<p id=\"caption-attachment-3620\" class=\"wp-caption-text\">Arrangement of US currency; money serves as a medium of financial exchange in economics.<\/p>\n<\/div>\n<h2>What are Polynomials and Rational Expressions Used For?<\/h2>\n<p>In economics we learn that <strong>profit<\/strong> is the difference between <strong>revenue<\/strong> (money coming in), and <strong>costs<\/strong> (money going out). \u00a0Positive profit means that there is a net inflow of money, while negative profit means that money is being lost.<\/p>\n<p>Suppose that you own a company that manufactures and sells furniture. \u00a0A particular chair sells for $40. If your company builds and sells 500 of these chairs in one month, then your monthly revenue would be $20,000. In general, if you manufacture and sell [latex]x[\/latex] chairs, then the revenue [latex]R[\/latex], in dollars, would be given by this formula:<\/p>\n<p style=\"text-align: center;\">[latex]R=40x[\/latex]<\/p>\n<p>&nbsp;<\/p>\n<p>Now let\u2019s talk about costs. Let\u2019s say it costs $10,000 each month just to keep the factory open, regardless of how many chairs are produced. This amount might include the electric and gas bills as well as the monthly paychecks for each of your employees. These costs, which do not depend on the number of items produced, are called the <strong>overhead<\/strong> costs. Furthermore, suppose the materials cost $25 per chair. That means that if we produced [latex]x[\/latex] chairs, then the total cost for materials would be [latex]$25x[\/latex]. Together with the overhead, we can derive a total estimated cost formula.<\/p>\n<p style=\"text-align: center;\">[latex]C=\\left(overhead\\right)+\\left(materials\\right)=10,000+25x[\/latex]<\/p>\n<p>&nbsp;<\/p>\n<p>Both formulas for revenue and cost are examples of <strong>polynomials<\/strong>. In fact both polynomials are what we call <strong>degree 1<\/strong>, or <strong>linear<\/strong> polynomials, because the variable [latex]x[\/latex] only occurs with exponent 1. \u00a0What is the profit formula? \u00a0Simply subtract the two expressions \u00a0(Profit = Revenue &#8211; Costs), to find:<\/p>\n<p style=\"text-align: center;\">[latex]P=R-C[\/latex]<\/p>\n<p style=\"text-align: center;\">[latex]P=\\left(40x\\right)-\\left(10,000+25x\\right)[\/latex]<\/p>\n<p style=\"text-align: center;\">[latex]P=40x-10,000-25x[\/latex]<\/p>\n<p style=\"text-align: center;\">[latex]P=15x-10,000[\/latex]<\/p>\n<p>&nbsp;<\/p>\n<p>Will your company make money if it manufactures and sells 500 chairs? \u00a0What about 800 chairs?<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-3671 alignleft\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/896\/2017\/03\/16230558\/40chair-192x300.jpg\" alt=\"Basic wooden chair with the price of $40.\" width=\"193\" height=\"301\" \/><\/p>\n<p>Now imagine that your small company has gotten more and more business over that past few months. You\u2019re producing so many chairs that you had to hire new employees, purchase new trucks and even plan for a larger factory. Those costs are adding up!<\/p>\n<p>&nbsp;<\/p>\n<p>After carefully analyzing monthly expenses, you estimate the additional costs (above and beyond the overhead and materials costs) to be modeled by a <strong>degree 2<\/strong> (or <strong>quadratic<\/strong>) term, [latex]0.001x^2[\/latex]. Here are your new cost and profit formulas:<\/p>\n<p style=\"text-align: center;\">[latex]C=10,000+15x+0.001x^2[\/latex]<\/p>\n<p style=\"text-align: center;\">[latex]P=40x-\\left(10,000+25x+0.001x^2\\right)=-0.001x^2+15x-10,000[\/latex]<\/p>\n<p>&nbsp;<\/p>\n<p>These new formulas are also polynomials, but they behave differently than the previous formulas for large values of [latex]x[\/latex].<\/p>\n<p>&nbsp;<\/p>\n<p>Finally, let\u2019s suppose you want to find out whether it is still cost-effective to produce your $40 chairs in mass quantities. Perhaps the best way to find out is to determine the <strong>average profit<\/strong> when [latex]x[\/latex] chairs are manufactured and sold. As always, an average is equal to the total amount ([latex]P[\/latex], for profit in this case) divided by the number of items ([latex]x[\/latex]).<\/p>\n<p style=\"text-align: center;\">[latex]\\Large\\frac{P}{x}=\\frac{-0.001x^2+15x-10,000}{x}[\/latex]<\/p>\n<p>&nbsp;<\/p>\n<p>This time, the formula for average profit is no longer a polynomial, but a <strong>rational function<\/strong>, which is the ratio of two polynomials.<\/p>\n<p>&nbsp;<\/p>\n<p>In this module, you\u2019ll learn how to classify and perform algebraic operations on polynomials and rational functions. We will check back in on our company\u2019s profits at the end of the module.<\/p>\n<h3><\/h3>\n<p>&nbsp;<\/p>\n<div class=\"textbox learning-objectives\">\n<h3>Learning Objectives<\/h3>\n<p>Polynomial Basics<\/p>\n<ul class=\"ul1\">\n<li class=\"li2\"><span class=\"s1\">Identify the degree, leading coefficient, and leading term of a polynomial expression<\/span><\/li>\n<li class=\"li2\"><span class=\"s1\">Perform algebraic operations on polynomial expressions<\/span><\/li>\n<\/ul>\n<p class=\"p1\"><span class=\"s1\">Factoring Polynomials<\/span><\/p>\n<ul class=\"ul1\">\n<li class=\"li2\"><span class=\"s1\">Identify the greatest common factor of a polynomial expression<\/span><\/li>\n<li class=\"li2\"><span class=\"s1\">Factor a wide variety of polynomials including those with fractional or negative exponents<\/span><\/li>\n<\/ul>\n<p class=\"p1\"><span class=\"s1\">Rational Expressions<\/span><\/p>\n<ul class=\"ul1\">\n<li class=\"li3\"><span class=\"s5\">Simplify and perform algebraic operations on rational expressions<\/span><\/li>\n<\/ul>\n<\/div>\n<p>&nbsp;<\/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-1219\">\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>Why It Matters: Polynomials and Rational Expressions. <strong>Authored 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>US Currency. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"https:\/\/pixabay.com\/en\/dollar-money-us-dollar-arrangement-1071788\/\">https:\/\/pixabay.com\/en\/dollar-money-us-dollar-arrangement-1071788\/<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/about\/cc0\">CC0: No Rights Reserved<\/a><\/em><\/li><li>$40 wooden chair. <strong>Authored by<\/strong>: Modified by S.V. Ault for Lumen. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/www.freestockphotos.biz\/stockphoto\/9530\">http:\/\/www.freestockphotos.biz\/stockphoto\/9530<\/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":21,"menu_order":1,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"US Currency\",\"author\":\"\",\"organization\":\"\",\"url\":\"https:\/\/pixabay.com\/en\/dollar-money-us-dollar-arrangement-1071788\/\",\"project\":\"\",\"license\":\"cc0\",\"license_terms\":\"\"},{\"type\":\"cc\",\"description\":\"$40 wooden chair\",\"author\":\"Modified by S.V. Ault for Lumen\",\"organization\":\"\",\"url\":\"http:\/\/www.freestockphotos.biz\/stockphoto\/9530\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"\"},{\"type\":\"original\",\"description\":\"Why It Matters: Polynomials and Rational Expressions\",\"author\":\"Lumen Learning\",\"organization\":\"\",\"url\":\"\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"\"}]","CANDELA_OUTCOMES_GUID":"c0bb1b90-1b00-4aae-befb-d1238c431468","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-1219","chapter","type-chapter","status-publish","hentry"],"part":1203,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/ivytech-wmopen-collegealgebra\/wp-json\/pressbooks\/v2\/chapters\/1219","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/ivytech-wmopen-collegealgebra\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/ivytech-wmopen-collegealgebra\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/ivytech-wmopen-collegealgebra\/wp-json\/wp\/v2\/users\/21"}],"version-history":[{"count":14,"href":"https:\/\/courses.lumenlearning.com\/ivytech-wmopen-collegealgebra\/wp-json\/pressbooks\/v2\/chapters\/1219\/revisions"}],"predecessor-version":[{"id":3773,"href":"https:\/\/courses.lumenlearning.com\/ivytech-wmopen-collegealgebra\/wp-json\/pressbooks\/v2\/chapters\/1219\/revisions\/3773"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/ivytech-wmopen-collegealgebra\/wp-json\/pressbooks\/v2\/parts\/1203"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/ivytech-wmopen-collegealgebra\/wp-json\/pressbooks\/v2\/chapters\/1219\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/ivytech-wmopen-collegealgebra\/wp-json\/wp\/v2\/media?parent=1219"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/ivytech-wmopen-collegealgebra\/wp-json\/pressbooks\/v2\/chapter-type?post=1219"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/ivytech-wmopen-collegealgebra\/wp-json\/wp\/v2\/contributor?post=1219"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/ivytech-wmopen-collegealgebra\/wp-json\/wp\/v2\/license?post=1219"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}