Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

Published by Pearson
ISBN 10: 0-32184-874-8
ISBN 13: 978-0-32184-874-1

Chapter 1-11 - Cumulative Review - Page 776: 12

Answer

$\left(3,\dfrac{1}{2}\right)$

Work Step by Step

Cancel the $x$-variable in the given system, \begin{align*} 2x-6y&=3 \\ -3x+8y&=-5 \end{align*} These result to the equivalent system, \begin{align*} 6x-18y&=9 &(1) \\ -6x+16y&=-10. &(2) \end{align*} Adding equations $(1)$ and $(2)$, and solving for the variable gives: \begin{align*} 0x-2y&=-1 \\ -2y&=-1 \\\\ \dfrac{-2y}{-2}&=\dfrac{-1}{-2} \\\\ y&=\dfrac{1}{2} .\end{align*} Substituting $y=\dfrac{1}{2}$ in the first given equation, $2x-6y=3,$ results to \begin{align*} 2x-6\left(\dfrac{1}{2}\right)&=3 \\\\ 2x-3&=3 \\ 2x&=3+3 \\ 2x&=6 \\\\ \dfrac{2x}{2}&=\dfrac{6}{2} \\\\ x&=3 .\end{align*} With $x=3$ and $y=\dfrac{1}{2},$ the solution to the given system is the ordered pair $ \left(3,\dfrac{1}{2}\right) $.
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