College Algebra (6th Edition)

Published by Pearson
ISBN 10: 0-32178-228-3
ISBN 13: 978-0-32178-228-1

Chapter 1 - Equations and Inequalities - Exercise Set 1.5 - Page 160: 56



Work Step by Step

To complete the square, add a term that is the square of half the coefficient of $x$ to both sides of the equation, and factor the left side. Then use the square root property to simplify both sides, and then isolate $x$. $x^2+7x-8=0$ $(\frac{7}{2})^2$ $x^2+7x-8+8+(\frac{7}{2})^2=8+(\frac{7}{2})^2$ $x^2+7x+(\frac{7}{2})^2=8+(\frac{7}{2})^2$ $x^2+7x+\frac{49}{4}=8+\frac{49}{4}$ $x^2+7x+\frac{49}{4}=\frac{81}{4}$ $(x+\frac{7}{2})^2=\frac{81}{4}$ $x+\frac{7}{2}=±\frac{9}{2}$ $x=-\frac{7}{2}±\frac{9}{2}$ $x=-8,1$
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