{"id":153,"date":"2025-02-15T22:20:20","date_gmt":"2025-02-15T16:50:20","guid":{"rendered":"https:\/\/deepwrites.com\/?p=153"},"modified":"2025-02-15T22:40:15","modified_gmt":"2025-02-15T17:10:15","slug":"solving-quadratic-and-cubic-equations-a-step-by-step-guide","status":"publish","type":"post","link":"https:\/\/deepwrites.com\/?p=153","title":{"rendered":"Solving Quadratic and Cubic Equations: A Step-by-Step Guide"},"content":{"rendered":"\n<figure class=\"wp-block-image size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"596\" height=\"336\" src=\"https:\/\/deepwrites.com\/wp-content\/uploads\/2025\/02\/quadratic.jpg\" alt=\"\" class=\"wp-image-154\" style=\"width:578px;height:auto\" srcset=\"https:\/\/deepwrites.com\/wp-content\/uploads\/2025\/02\/quadratic.jpg 596w, https:\/\/deepwrites.com\/wp-content\/uploads\/2025\/02\/quadratic-300x169.jpg 300w\" sizes=\"(max-width: 596px) 100vw, 596px\" \/><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Solving Quadratic and Cubic Equations: A Step-by-Step Guide<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Introduction<\/h3>\n\n\n\n<p>Quadratic and cubic equations are fundamental in algebra and appear in various real-world applications. A quadratic equation is of the form <em>ax<\/em><sup>2<\/sup> +<em>bx<\/em>+<em>c<\/em>= 0, while a cubic equation is of the form <em>ax<\/em><sup>3<\/sup> +<em>bx<\/em><sup>2<\/sup> +<em>cx<\/em>+ <em>d <\/em>= 0. In this article, we will explore different methods to solve these equations, with clear explanations for each step.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Solving Quadratic Equations<\/h3>\n\n\n\n<p>A quadratic equation is of the form:<\/p>\n\n\n\n<p><em>ax<\/em><sup>2<\/sup> + <em>bx <\/em>+ <em>c<\/em><em> <\/em>= 0&nbsp; (<em>a <\/em><em><\/em>= 0)<\/p>\n\n\n\n<p>There are several methods to solve quadratic equations: factoring, completing the square, and using the quadratic formula.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Method 1: Factoring<\/h3>\n\n\n\n<p>Factoring is the simplest method when the quadratic can be expressed as a product of two binomials.<\/p>\n\n\n\n<p>Steps:<\/p>\n\n\n\n<ol>\n<li>Write the equation in standard form: <em>ax<\/em><sup>2<\/sup> + <em>bx <\/em>+ <em>c <\/em>= 0.<\/li>\n\n\n\n<li>Factor the quadratic into two binomials: (<em>px <\/em>+ <em>q<\/em>)(<em>rx <\/em>+ <em>s<\/em>) = 0(Many times in such a case, we can factor c into multiples and try to find two multiples m,n such that m + n = b. Then break b into m,n and try to being the form as in the next step).<\/li>\n\n\n\n<li>Set each binomial equal to zero and solve for <em>x<\/em>:<\/li>\n<\/ol>\n\n\n\n<p>                                                         <em>px <\/em>+ <em>q<\/em><em> <\/em>= 0\u00a0 or\u00a0 <em>rx <\/em>+ <em>s<\/em><em> <\/em>= 0<\/p>\n\n\n\n<p>4. The solutions are:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<\/p>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" width=\"8\" height=\"2\" src=\"\"><img loading=\"lazy\" decoding=\"async\" width=\"8\" height=\"2\" src=\"\"><em>x<\/em><em> <\/em>= <em>\u2212<\/em><em>p<\/em><em>&nbsp;&nbsp;&nbsp; <\/em>and&nbsp; <em>x <\/em>= <em>\u2212<\/em><em>r<\/em><em><\/em><\/p>\n\n\n\n<p>Example: Solve <em>x<\/em><sup>2<\/sup> <em>\u2212 <\/em>5<em>x <\/em>+ 6 = 0. We note before starting the solution that 6 = (<em>\u2212<\/em>3)(<em>\u2212<\/em>2) and (<em>\u2212<\/em>3) + (<em>\u2212<\/em>2) = (<em>\u2212<\/em>5) = <em>b<\/em><\/p>\n\n\n\n<p><em>x<\/em><sup>2<\/sup> <em>\u2212 <\/em>5<em>x <\/em>+ 6 = 0<\/p>\n\n\n\n<p><em>x<\/em><sup>2<\/sup> <em>\u2212 <\/em>3<em>x <\/em><em>\u2212 <\/em>2<em>x <\/em>+ 6 = 0<\/p>\n\n\n\n<p>(<em>x <\/em><em>\u2212 <\/em>2)(<em>x <\/em><em>\u2212 <\/em>3) = 0<\/p>\n\n\n\n<p><em>x <\/em><em>\u2212 <\/em>2 = 0&nbsp; or&nbsp; <em>x <\/em><em>\u2212 <\/em>3 = 0<\/p>\n\n\n\n<p><em>x<\/em><em> <\/em>= 2\u00a0 or\u00a0 <em>x<\/em><em> <\/em>= 3<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Method 2: Completing the Square<\/h2>\n\n\n\n<p>Completing the square is a method that works for all quadratic equations.<\/p>\n\n\n\n<p>Steps:<\/p>\n\n\n\n<ol>\n<li>Write the equation in standard form: <em>ax<\/em><sup>2<\/sup> + <em>bx <\/em>+ <em>c <\/em>= 0.<\/li>\n<\/ol>\n\n\n\n<p>Divide both sides by <em>a <\/em>(if <em>a <\/em><em><\/em>= 1): <em>x<\/em><sup>2<\/sup> + <sup>&nbsp;<\/sup><em><u><sup>b<\/sup><\/u><\/em><em> <\/em><em>x <\/em>+ <sup>&nbsp;<\/sup><em><u><sup>c<\/sup><\/u><\/em><em> <\/em>= 0.<\/p>\n\n\n\n<ul>\n<li>Move the constant term to the other side: <em>x<\/em><sup>2<\/sup> + <sup>\u00a0<\/sup><em><u><sup>b<\/sup><\/u><\/em><em> <\/em><em>x <\/em>= <em>\u2212 <\/em><em><u>\u00a0<\/u><\/em><em><u>c<\/u><\/em><em>\u00a0<\/em>.<\/li>\n<\/ul>\n\n\n\n<p><em>a<\/em><em>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; a<\/em><\/p>\n\n\n\n<ul>\n<li><\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td>2<em>a<\/em><em><\/em> &nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>Add <em><u>&nbsp;<\/u><\/em><em><u>b <\/u><\/em>&nbsp;2 to both sides to complete the square:<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td>&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td>&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p><em>x<\/em><sup>2<\/sup> + <em><u>b<\/u><\/em><em>&nbsp;<\/em><em>x <\/em>+<\/p>\n\n\n\n<p><em>a<\/em><em><\/em><br><\/p>\n\n\n\n<p><em><u>&nbsp;<\/u><\/em><em><u>b<\/u><\/em><em>&nbsp;&nbsp;&nbsp;&nbsp; <\/em><sup>2<\/sup>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <em><u>c<\/u><\/em><\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td><em>\u2014<\/em><em><\/em> &nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>=&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; +<\/p>\n\n\n\n<p>2<em>a<\/em><em>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; a<\/em><br><\/p>\n\n\n\n<p><em><u>&nbsp;<\/u><\/em><em><u>b<\/u><\/em><em>&nbsp;&nbsp;&nbsp;&nbsp; <\/em><sup>2<\/sup><\/p>\n\n\n\n<p>2<em>a<\/em><em><\/em><em><br><\/em><em><br><\/em><\/p>\n\n\n\n<ul>\n<li>Rewrite the left side as a perfect square:<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td><em>x <\/em>+2<em>a<\/em><em><\/em> &nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p><em><u>&nbsp;<\/u><\/em><em><u>b<\/u><\/em>&nbsp; 2<br><\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td>= &nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p><em>b<\/em><sup>2<\/sup> <em>\u2212 <\/em>4<em>ac<\/em><em><\/em><\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"\" alt=\"\"\/><\/figure>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"\" alt=\"Text Box: 4a2\"\/><\/figure>\n\n\n\n<p><em><br><\/em><\/p>\n\n\n\n<ul>\n<li>Take the square root of both sides:<\/li>\n<\/ul>\n\n\n\n<ul>\n<li>Solve for <em>x<\/em>:<\/li>\n<\/ul>\n\n\n\n<p><em>b<\/em><em><\/em><\/p>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" width=\"15\" height=\"2\" src=\"\"><em>x <\/em>+ 2<em>a<\/em><em>&nbsp;<\/em>= <em>\u00b1<\/em><em><\/em><br><\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td><\/td><\/tr><tr><td><\/td><td><img loading=\"lazy\" decoding=\"async\" width=\"52\" height=\"2\" src=\"\"><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p><em>b<\/em>2 <em>\u2212 <\/em>4<em>ac <\/em>4<em>a<\/em>2<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"\" alt=\"\"\/><\/figure>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"\" alt=\"\"\/><\/figure>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td>r &nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p><em>\u221a <\/em>2<\/p>\n\n\n\n<p>Example: Solve <em>x<\/em><sup>2<\/sup> <em>\u2212 <\/em>4<em>x <\/em><em>\u2212 <\/em>5 = 0.<br><\/p>\n\n\n\n<p><em>b<\/em><em><\/em><\/p>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" width=\"15\" height=\"2\" src=\"\"><em>x <\/em>= <em>\u2212 <\/em>2<em>a<\/em><em>&nbsp;<\/em><em>\u00b1<\/em><em><\/em><br><\/p>\n\n\n\n<p><em>b <\/em><em>\u2212 <\/em>4<em>ac<\/em><em><\/em><\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"\" alt=\"\"\/><\/figure>\n\n\n\n<p>2<em>a<\/em><em><\/em><em><br><\/em><em><br><\/em><\/p>\n\n\n\n<p><em>x<\/em><sup>2<\/sup> <em>\u2212 <\/em>4<em>x<\/em><em> <\/em>= 5<\/p>\n\n\n\n<p><em>x<\/em><sup>2<\/sup> <em>\u2212 <\/em>4<em>x <\/em>+ 4 = 5 + 4&nbsp; (Add (<em>x <\/em><em>\u2212 <\/em>2)<sup>2<\/sup> = 9<\/p>\n\n\n\n<p><em>x <\/em><em>\u2212 <\/em>2 = <em>\u00b1<\/em>3<\/p>\n\n\n\n<p><em>x <\/em>= 2 <em>\u00b1 <\/em>3<br><\/p>\n\n\n\n<p>&nbsp;<em><u>\u2212<\/u><\/em>4&nbsp;<sub>2<\/sub><\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td><\/td><\/tr><tr><td><\/td><td><img loading=\"lazy\" decoding=\"async\" width=\"10\" height=\"17\" src=\"\" alt=\"Text Box: 2\"><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>= 4)<\/p>\n\n\n\n<p><em>x<\/em><em> <\/em>= 5&nbsp; or&nbsp; <em>x<\/em><em> <\/em>= <em>\u2212<\/em>1<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Method 3: Quadratic Formula<\/h2>\n\n\n\n<p>The quadratic formula is a universal method for solving any quadratic equation.<\/p>\n\n\n\n<p>Formula:<\/p>\n\n\n\n<p>Steps:<br><\/p>\n\n\n\n<p><em>x <\/em>= <em>\u2212<\/em><em>b <\/em><em>\u00b1<\/em><em><\/em><br><\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td><em>\u221a<\/em><em><\/em> &nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p><em>b<\/em>2 <em>\u2212 <\/em>4<em>ac<\/em><em><\/em><\/p>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" width=\"92\" height=\"2\" src=\"\">2<em>a<\/em><em><\/em><em><br><\/em><\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"\" alt=\"\"\/><\/figure>\n\n\n\n<ol>\n<li>Identify <em>a<\/em>, <em>b<\/em>, and <em>c <\/em>in the equation <em>ax<\/em><sup>2<\/sup> + <em>bx <\/em>+ <em>c <\/em>= 0.<\/li>\n\n\n\n<li>Substitute these values into the quadratic formula.<\/li>\n\n\n\n<li>Simplify under the square root (the discriminant).<\/li>\n\n\n\n<li>Calculate the two solutions using + and <em>\u2212<\/em>.<\/li>\n<\/ol>\n\n\n\n<p>Example: Solve 2<em>x<\/em><sup>2<\/sup> + 4<em>x <\/em><em>\u2212 <\/em>6 = 0.<br><\/p>\n\n\n\n<p><em>a<\/em><em> <\/em>= 2<em>,<\/em><em>&nbsp;&nbsp;&nbsp;&nbsp; b <\/em>= &nbsp;4<em>,<\/em><em><u>&nbsp;&nbsp;&nbsp;&nbsp; c <\/u><\/em>= <em><u>\u2212<\/u><\/em>6<\/p>\n\n\n\n<p><em>\u2212<\/em>4 <em>\u00b1 <\/em>\u221a42 <em>\u2212 <\/em>4(2)(<em>\u2212<\/em>6)<\/p>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" width=\"127\" height=\"2\" src=\"\"><em>x <\/em>=<\/p>\n\n\n\n<p>2(2)<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"\" alt=\"\"\/><\/figure>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"\" alt=\"\"\/><\/figure>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td>4 &nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p><em>x <\/em>= <em>\u2212<\/em>4 <em>\u00b1 \u221a<\/em>16 + 48<\/p>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" width=\"15\" height=\"2\" src=\"\"><img loading=\"lazy\" decoding=\"async\" width=\"59\" height=\"2\" src=\"\"><em>x <\/em>= <em>\u2212<\/em>4 <em>\u00b1 \u221a<\/em>64<\/p>\n\n\n\n<p>4<\/p>\n\n\n\n<p><em>x<\/em><em>&nbsp;<\/em>= <em><u>\u2212<\/u><\/em>4 <em><u>\u00b1 <\/u><\/em>8<\/p>\n\n\n\n<p>4<\/p>\n\n\n\n<p><em>x<\/em><em> <\/em>= 1&nbsp; or&nbsp; <em>x<\/em><em> <\/em>= <em>\u2212<\/em>3<\/p>\n\n\n\n<h1 class=\"wp-block-heading\">Solving Cubic Equations<\/h1>\n\n\n\n<p>A cubic equation is of the form:<\/p>\n\n\n\n<p><em>ax<\/em><sup>3<\/sup> + <em>bx<\/em><sup>2<\/sup> + <em>cx <\/em>+ <em>d<\/em><em> <\/em>= 0&nbsp; (<em>a <\/em><em><\/em>= 0)<\/p>\n\n\n\n<p>Solving cubic equations is more complex than solving quadratics. Here, we will discuss the Rational Root Theorem and synthetic division.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Method 1: Rational Root Theorem<\/h2>\n\n\n\n<p>The Rational Root Theorem helps identify possible rational roots of a polynomial equation.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td><\/td><\/tr><tr><td><\/td><td><img loading=\"lazy\" decoding=\"async\" width=\"36\" height=\"2\" src=\"\"><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>Steps:<\/p>\n\n\n\n<ol>\n<li>List all factors of the constant term <em>d <\/em>and the leading coefficient <em>a<\/em>.<\/li>\n\n\n\n<li><\/li>\n<\/ol>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td>factor of <em>a<\/em><em><\/em> &nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>The possible rational roots are of the form <sup>factor<\/sup> <sup>of<\/sup> <em><sup>d<\/sup><\/em><em> <\/em>.<\/p>\n\n\n\n<ul>\n<li>Test these possible roots by substituting them into the equation.<\/li>\n\n\n\n<li>Once a root <em>r <\/em>is found, factor the polynomial as (<em>x <\/em><em>\u2212 <\/em><em>r<\/em>) <em>\u00b7 <\/em><em>Q<\/em>(<em>x<\/em>), where <em>Q<\/em>(<em>x<\/em>) is a quadratic.<\/li>\n\n\n\n<li>Solve the quadratic equation <em>Q<\/em>(<em>x<\/em>) = 0 using methods for quadratics. Example: Solve <em>x<\/em><sup>3<\/sup> <em>\u2212 <\/em>6<em>x<\/em><sup>2<\/sup> + 11<em>x <\/em><em>\u2212 <\/em>6 = 0.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td>2 &nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>Possible roots = <em>\u00b1<\/em>1<em>, <\/em><em>\u00b1<\/em>2<em>, <\/em><em>\u00b1<\/em>3<em>, <\/em><em>\u00b1<\/em>6 Test <em>x <\/em>= 1 :&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 1 <em>\u2212 <\/em>6 + 11 <em>\u2212 <\/em>6 = 0 (Root found) Factor: (<em>x <\/em><em>\u2212 <\/em>1)(<em>x <\/em><em>\u2212 <\/em>5<em>x <\/em>+ 6) = 0<\/p>\n\n\n\n<p>Solve <em>x<\/em><sup>2<\/sup> <em>\u2212 <\/em>5<em>x <\/em>+ 6 = 0 (<em>x <\/em><em>\u2212 <\/em>2)(<em>x <\/em><em>\u2212 <\/em>3) = 0<\/p>\n\n\n\n<p><em>x <\/em>= 1<em>, <\/em>2<em>, <\/em>3<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Method 2: Synthetic Division<\/h2>\n\n\n\n<p>Synthetic division is a shortcut for dividing polynomials when a root is known.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td><\/td><\/tr><tr><td><\/td><td><img loading=\"lazy\" decoding=\"async\" width=\"36\" height=\"2\" src=\"\"><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>Steps:<\/p>\n\n\n\n<ol>\n<li>Identify a root <em>r <\/em>using the Rational Root Theorem.<\/li>\n\n\n\n<li>Use synthetic division to divide the polynomial by (<em>x <\/em><em>\u2212 <\/em><em>r<\/em>).<\/li>\n\n\n\n<li>Rewrite the polynomial as (<em>x <\/em><em>\u2212 <\/em><em>r<\/em>) <em>\u00b7 <\/em><em>Q<\/em>(<em>x<\/em>).<\/li>\n\n\n\n<li>Solve the quadratic equation <em>Q<\/em>(<em>x<\/em>) = 0.<\/li>\n<\/ol>\n\n\n\n<p>Example: Solve <em>x<\/em><sup>3<\/sup> <em>\u2212 <\/em>4<em>x<\/em><sup>2<\/sup> + <em>x <\/em>+ 6 = 0.<\/p>\n\n\n\n<p>Possible roots = <em>\u00b1<\/em>1<em>,<\/em><em> <\/em><em>\u00b1<\/em>2<em>,<\/em><em> <\/em><em>\u00b1<\/em>3<em>,<\/em><em> <\/em><em>\u00b1<\/em>6<\/p>\n\n\n\n<p>Test <em>x <\/em>= 2 :&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 8 <em>\u2212 <\/em>16 + 2 + 6 = 0&nbsp; (Root found) Synthetic division:<\/p>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" width=\"132\" height=\"50\" src=\"\">2&nbsp; 1&nbsp; <em>\u2212<\/em>4&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 1&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 6<\/p>\n\n\n\n<p>2&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <em>\u2212<\/em>4&nbsp; <em>\u2212<\/em>6<\/p>\n\n\n\n<p>1&nbsp; <em>\u2212<\/em>2&nbsp; <em>\u2212<\/em>3&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0<\/p>\n\n\n\n<p>Factor: (<em>x <\/em><em>\u2212 <\/em>2)(<em>x<\/em><sup>2<\/sup> <em>\u2212 <\/em>2<em>x <\/em><em>\u2212 <\/em>3) = 0<\/p>\n\n\n\n<p>Solve <em>x<\/em><sup>2<\/sup> <em>\u2212 <\/em>2<em>x <\/em><em>\u2212 <\/em>3 = 0 (<em>x <\/em><em>\u2212 <\/em>3)(<em>x<\/em><em> <\/em>+ 1) = 0<\/p>\n\n\n\n<p><em>x <\/em>= 2<em>, <\/em>3<em>, <\/em><em>\u2212<\/em>1<\/p>\n\n\n\n<h1 class=\"wp-block-heading\">1&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Vieta\u2019s formula to solve quadratic\u2019s and cubic\u2019s :<\/h1>\n\n\n\n<p>Vieta\u2019s formulas provide a powerful tool for solving polynomial equations by establishing relationships between the coefficients and the roots of the equation. These formulas are particularly useful for quadratic and cubic equations, as they allow us to determine the roots without explicitly factoring the polynomial. Let us explore this step by step.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Quadratic Equations<\/h2>\n\n\n\n<p>Consider a general quadratic equation of the form:<\/p>\n\n\n\n<p><em>ax<\/em><sup>2<\/sup> + <em>bx <\/em>+ <em>c <\/em>= 0<em>,<\/em><em><\/em><\/p>\n\n\n\n<p>where <em>a <\/em><em><\/em>= 0. If the roots of this equation are <em>\u03b1 <\/em>and <em>\u03b2<\/em>, Vieta\u2019s formulas state that:<\/p>\n\n\n\n<p><em>b<\/em><em><\/em><\/p>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" width=\"8\" height=\"2\" src=\"\"><em>\u03b1<\/em><em> <\/em>+ <em>\u03b2<\/em><em> <\/em>= <em>\u2212<\/em><em>a<\/em><em>&nbsp;&nbsp;&nbsp;&nbsp; <\/em>(Sum of the roots)<em>,<\/em><em><\/em><\/p>\n\n\n\n<p><em>c<\/em><em><\/em><em><br><\/em><\/p>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" width=\"8\" height=\"2\" src=\"\"><em>\u03b1\u03b2<\/em><em> <\/em>=<\/p>\n\n\n\n<p><em>a<\/em><em><\/em><br><\/p>\n\n\n\n<p>(Product of the roots)<em>.<\/em><em><\/em><em><br><\/em><\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td><em>\u2212<\/em><em>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; \u2212<\/em> &nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>These relationships arise from expanding the factored form of the quadratic equation, <em>a<\/em>(<em>x<\/em><em> \u03b1<\/em>)(<em>x<\/em><em> \u03b2<\/em>) = 0, and comparing coefficients. To solve for the roots, we can use these formulas as follows:<\/p>\n\n\n\n<ol>\n<li><\/li>\n<\/ol>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td><em>a<\/em><em><\/em> &nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>Compute the sum of the roots, <em>\u03b1 <\/em>+ <em>\u03b2<\/em>, using <em>\u2212 <\/em><em><u>&nbsp;<\/u><\/em><em><u>b<\/u><\/em><em>&nbsp;<\/em>.<\/p>\n\n\n\n<ul>\n<li><\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td><em>a<\/em><em><\/em> &nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>Compute the product of the roots, <em>\u03b1\u03b2<\/em>, using <sup>&nbsp;<\/sup><em><u><sup>c<\/sup><\/u><\/em><em> <\/em>.<\/p>\n\n\n\n<ul>\n<li>Find two numbers that satisfy both the sum and product conditions. For example, if <em>\u03b1 <\/em>+ <em>\u03b2<\/em><em> <\/em>= 5 and <em>\u03b1\u03b2 <\/em>= 6, the roots are 2 and 3, since 2 + 3 = 5 and 2 <em>\u00b7 <\/em>3 = 6.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Cubic Equations<\/h2>\n\n\n\n<p>For a general cubic equation of the form:<\/p>\n\n\n\n<p><em>ax<\/em><sup>3<\/sup> + <em>bx<\/em><sup>2<\/sup> + <em>cx <\/em>+ <em>d <\/em>= 0<em>, <\/em>where <em>a <\/em><em><\/em>= 0, if the roots are <em>\u03b1<\/em>, <em>\u03b2<\/em>, and <em>\u03b3<\/em>, Vieta\u2019s formulas extend to:<\/p>\n\n\n\n<p><em>b<\/em><em><\/em><\/p>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" width=\"8\" height=\"2\" src=\"\"><em>\u03b1<\/em><em> <\/em>+ <em>\u03b2<\/em><em> <\/em>+ <em>\u03b3<\/em><em> <\/em>= <em>\u2212<\/em><em>a<\/em><em>&nbsp;&nbsp;&nbsp;&nbsp; <\/em>(Sum of the roots)<em>,<\/em><em><\/em><em><br><\/em><\/p>\n\n\n\n<p><em>c<\/em><em><\/em><\/p>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" width=\"9\" height=\"2\" src=\"\"><em>\u03b1\u03b2 <\/em>+ <em>\u03b1\u03b3 <\/em>+ <em>\u03b2\u03b3 <\/em>=<\/p>\n\n\n\n<p><em>a<\/em><em><\/em><br><\/p>\n\n\n\n<p>(Sum of the products of the roots taken two at a time)<em>,<\/em><em><\/em><\/p>\n\n\n\n<p><em>d<\/em><em><\/em><\/p>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" width=\"8\" height=\"2\" src=\"\"><em>\u03b1\u03b2\u03b3<\/em><em> <\/em>= <em>\u2212<\/em><em>a<\/em><em>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <\/em>(Product of the roots)<em>.<\/em><em><\/em><em><br><\/em><\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td><em>\u2212<\/em><em>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; \u2212&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; \u2212<\/em> &nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>These relationships are derived from expanding the factored form <em>a<\/em>(<em>x<\/em><em>&nbsp; \u03b1<\/em>)(<em>x<\/em><em>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; \u03b2<\/em>)(<em>x<\/em><em>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; \u03b3<\/em>) = 0 and comparing coefficients. To solve for the roots, follow these steps:<\/p>\n\n\n\n<ol>\n<li><\/li>\n<\/ol>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td><em>a<\/em><em><\/em> &nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>Compute the sum of the roots, <em>\u03b1 <\/em>+ <em>\u03b2 <\/em>+ <em>\u03b3<\/em>, using <em>\u2212 <\/em><em>&nbsp;<\/em><em>b<\/em><em>&nbsp;<\/em>.<\/p>\n\n\n\n<ul>\n<li><\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td><em>a<\/em><em><\/em> &nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>Compute the sum of the products of the roots taken two at a time, <em>\u03b1\u03b2 <\/em>+ <em>\u03b1\u03b3 <\/em>+ <em>\u03b2\u03b3<\/em>, using <sup>&nbsp;<\/sup><em><sup>c<\/sup><\/em><em> <\/em>.<\/p>\n\n\n\n<ul>\n<li><\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td><em>a<\/em><em><\/em> &nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>Compute the product of the roots, <em>\u03b1\u03b2\u03b3<\/em>, using <em>\u2212<\/em><em>d<\/em><em>&nbsp;<\/em>.<\/p>\n\n\n\n<ul>\n<li>Use these values to construct a system of equations and solve for <em>\u03b1<\/em>, <em>\u03b2<\/em>, and <em>\u03b3<\/em>. For example, if <em>\u03b1 <\/em>+ <em>\u03b2 <\/em>+ <em>\u03b3<\/em><em> <\/em>= 6, <em>\u03b1\u03b2 <\/em>+ <em>\u03b1\u03b3 <\/em>+ <em>\u03b2\u03b3<\/em><em> <\/em>= 11, and <em>\u03b1\u03b2\u03b3<\/em><em> <\/em>= 6, the roots are 1, 2, and 3, since they satisfy all three conditions.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Key Insights<\/h2>\n\n\n\n<p>Vieta\u2019s formulas are particularly useful because they allow us to work directly with the symmetric sums and products of the roots, bypassing the need for explicit factoring. This method is especially helpful when the roots are integers or simple fractions, as it reduces the problem to solving a system of equations. For more complex roots, Vieta\u2019s formulas can still provide valuable insights into the relationships between the roots and coefficients, even if additional techniques (such as the quadratic or cubic formula) are required to find the exact values.<\/p>\n\n\n\n<h1 class=\"wp-block-heading\">Conclusion<\/h1>\n\n\n\n<p>Solving quadratic and cubic equations requires understanding different methods and practicing them. For quadratics, factoring, completing the square, and the quadratic formula are effective. For cubics, the Rational Root Theorem and synthetic division are useful tools. With practice, these methods become intuitive and powerful for solving polynomial equations.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>These are some step by step guides to solve quadratic equations and cubic equations. <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"image","meta":{"footnotes":""},"categories":[15],"tags":[21,19,17,18,20,23,22,24],"_links":{"self":[{"href":"https:\/\/deepwrites.com\/index.php?rest_route=\/wp\/v2\/posts\/153"}],"collection":[{"href":"https:\/\/deepwrites.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/deepwrites.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/deepwrites.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/deepwrites.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=153"}],"version-history":[{"count":5,"href":"https:\/\/deepwrites.com\/index.php?rest_route=\/wp\/v2\/posts\/153\/revisions"}],"predecessor-version":[{"id":163,"href":"https:\/\/deepwrites.com\/index.php?rest_route=\/wp\/v2\/posts\/153\/revisions\/163"}],"wp:attachment":[{"href":"https:\/\/deepwrites.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=153"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/deepwrites.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=153"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/deepwrites.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=153"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}