Intermediate Algebra (6th Edition)

Published by Pearson
ISBN 10: 0321785045
ISBN 13: 978-0-32178-504-6

Chapter 8 - Section 8.3 - Solving Equations by Using Quadratic Methods - Exercise Set - Page 501: 12

Answer

$\left\{ \dfrac{5-\sqrt{33}}{2},\dfrac{5+\sqrt{33}}{2} \right\}$

Work Step by Step

Factoring the given expression and then multiplying both sides of the given equation, $ \dfrac{11}{2x^2+x-15}=\dfrac{5}{2x-5}-\dfrac{x}{x+3} ,$ by the $LCD= (2x-5)(x+3) $, then, \begin{array}{l}\require{cancel} \dfrac{11}{(2x-5)(x+3)}=\dfrac{5}{2x-5}-\dfrac{x}{x+3} \\\\ (2x-5)(x+3)\left( \dfrac{11}{(2x-5)(x+3)} \right)=\left( \dfrac{5}{2x-5}-\dfrac{x}{x+3} \right)(2x-5)(x+3) \\\\ 1(11)=5(x+3)-x(2x-5) \\\\ 11=5x+15-2x^2+5x \\\\ 2x^2+(-5x-5x)+(11-15)=0 \\\\ 2x^2-10x-4=0 \\\\ \dfrac{2x^2-10x-4}{2}=\dfrac{0}{2} \\\\ x^2-5x-2=0 .\end{array} Using $\dfrac{-b\pm\sqrt{b^2-4ac}}{2a}$ (or the Quadratic Formula), the solutions of the quadratic equation, $ x^2-5x-2=0 ,$ are \begin{array}{l}\require{cancel} \dfrac{-(-5)\pm\sqrt{(-5)^2-4(1)(-2)}}{2(1)} \\\\= \dfrac{5\pm\sqrt{25+8}}{2} \\\\= \dfrac{5\pm\sqrt{33}}{2} .\end{array} Upon checking, both solutions satisfy the original equation. Hence, the solutions are $ \left\{ \dfrac{5-\sqrt{33}}{2},\dfrac{5+\sqrt{33}}{2} \right\} .$
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.