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: 7

Answer

$\left\{ 3-\sqrt{7},3+\sqrt{7} \right\}$

Work Step by Step

Multiplying both sides of the given equation, $ \dfrac{2}{x}+\dfrac{3}{x-1}=1 ,$ by the $LCD= x(x-1) $, then, \begin{array}{l}\require{cancel} x(x-1)\left( \dfrac{2}{x}+\dfrac{3}{x-1} \right)=\left( 1 \right)x(x-1) \\\\ (x-1)(2)+x(3)=x(x-1) \\\\ 2x-2+3x=x^2-x \\\\ -x^2+(2x+3x+x)-2=0 \\\\ -x^2+6x-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+6x-2=0 ,$ are \begin{array}{l}\require{cancel} \dfrac{-(6)\pm\sqrt{(6)^2-4(-1)(-2)}}{2(-1)} \\\\= \dfrac{-6\pm\sqrt{36-8}}{-2} \\\\= \dfrac{-6\pm\sqrt{28}}{-2} \\\\= \dfrac{-6\pm\sqrt{4\cdot7}}{-2} \\\\= \dfrac{-6\pm\sqrt{(2)^2\cdot7}}{-2} \\\\= \dfrac{-6\pm2\sqrt{7}}{-2} \\\\= \dfrac{-2(3\pm\sqrt{7})}{-2} \\\\= \dfrac{\cancel{-2}(3\pm\sqrt{7})}{\cancel{2}} \\\\= 3\pm\sqrt{7} .\end{array} Upon checking, both solutions satisfy the original equation. Hence, the solutions are $ \left\{ 3-\sqrt{7},3+\sqrt{7} \right\} .$
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