Precalculus (10th Edition)

Published by Pearson
ISBN 10: 0-32197-907-9
ISBN 13: 978-0-32197-907-0

Appendix A - Review - A.6 Solving Equations - A.6 Assess Your Understanding - Page A51: 46

Answer

$\{2,5\}$

Work Step by Step

Use distributive property. $\begin{align*} 2x(x)-2x(5)&=4(x)-4(5)\\ 2x^2-10x&=4x-20 \end{align*}$ Add $-4x+20$ to both sides. $2x^2-10x-4x+20=4x-20-4x+20$ Simplify. $2x^2-14x+20=0$ Divide both sides of the equation by $2$. $x^2-7x+10=0$ Rewrite $-7x$ as $-5x-2x$ $x^2-5x-2x+10=0$ Group the first two terms together and group the last two terms together. $(x^2-5x)+(-2x+10)=0$ Factor out the GCF of each group. $x(x-5)-2(x-5)=0$ Factor out $(x-5)$. $(x-5)(x-2)=0$ Use Zero-Product Property. $x-5=0$ or $x-2=0$ Solve each equation for $x$. $x=5$ or $x=2$ Hence, the solution set of the equation is $\{2,5\}$.
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