Intermediate Algebra for College Students (7th Edition)

Published by Pearson
ISBN 10: 0-13417-894-7
ISBN 13: 978-0-13417-894-3

Chapter 5 - Cumulative Review Exercises - Page 402: 7

Answer

$\{-5,0,2\}$.

Work Step by Step

Subtract $20x$ from both sides of the given equation. $2x^3+6x^2-20x=20x-20x$ Add like terms. $2x^3+6x^2-20x=0$ Factor out $2x$ from all terms. $2x(x^2+3x-10)=0$ Rewrite the middle term $3x$ as $5x-2x$. $2x(x^2+5x-2x-10)=0$ Group terms. $2x[(x^2+5x)+(-2x-10)]=0$ Factor each term. $2x[x(x+5)-2(x+5)]=0$ Factor out $(x+5)$. $2x(x+5)(x-2)=0$ Plug each factor equal to zero. $2x=0 $ or $x+5=0$ or $x-2=0$ Isolate $x$. $x=0$ or $x=-5$ or $x=2$. The solution set is $\{-5,0,2\}$.
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