Intermediate Algebra (6th Edition)

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

Chapter 8 - Section 8.2 - Solving Quadratic Equations by the Quadratic Formula - Exercise Set - Page 492: 22

Answer

$\left\{ \dfrac{5}{7},1 \right\}$

Work Step by Step

The standard form of the given equation, $ 7p(p-2)+2(p+4)=3 ,$ is \begin{array}{l}\require{cancel} 7p^2-14p+2p+8=3 \\\\ 7p^2+(-14p+2p)+(8-3)=0 \\\\ 7p^2-12p+5=0 .\end{array} Using $\dfrac{-b\pm\sqrt{b^2-4ac}}{2a}$ (or the Quadratic Formula), the solutions of the quadratic equation, $ 7p^2-12p+5=0 ,$ are \begin{array}{l}\require{cancel} \dfrac{-(-12)\pm\sqrt{(-12)^2-4(7)(5)}}{2(7)} \\\\= \dfrac{12\pm\sqrt{144-140}}{14} \\\\= \dfrac{12\pm\sqrt{4}}{14} \\\\= \dfrac{12\pm\sqrt{(2)^2}}{14} \\\\= \dfrac{12\pm2}{14} \\\\= \dfrac{12-2}{14} \text{ OR } \dfrac{12+2}{14} \\\\= \dfrac{10}{14} \text{ OR } \dfrac{14}{14} \\\\= \dfrac{5}{7} \text{ OR } 1 .\end{array} Hence, the solutions are $ \left\{ \dfrac{5}{7},1 \right\} .$
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