Intermediate Algebra (6th Edition)

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

Chapter 8 - Sections 8.1-8.3 - Integrated Review - Summary on Solving Quadratic Equations: 25


The solution set is $\left\{-11, 6\right\}$.

Work Step by Step

Multiply the left side: $x^2+5x=66$ Subtract 66 to both sides: $x^2 + 5x - 66 = 66-0 \\x^2+5x-66=0$ Factor the trinomial by looking for factors of $-66$ whose sum is equal to 5. These factors are 11 and $-6$. $(x+11)(x-6)=0$ Equate each factor to zero, then solve each equation. $x+11=0 \text{ o } x-6=0 \\x=-11 \text{ or }x=6$
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