Precalculus (6th Edition) Blitzer

Published by Pearson
ISBN 10: 0-13446-914-3
ISBN 13: 978-0-13446-914-0

Chapter 7 - Mid-Chapter Check Point - Page 853: 7


$(-1, 2, -2)$

Work Step by Step

Re-arrange the given two equations to get $4x-2y+4z=-16 $ and $6x-2y-8z =6$ $5x+z=-7 \implies 55x+11z =-77$ ....(1) and $7x-11z=15$ ...(2) $(55x+11z)+(7x-11z)=-77+15$ This gives: $x=-1$ Now, $5(-1)+z=-7 \implies z=-2$ and $2(-1)-y+2(-2)=-8 $ gives: $y=2$ Our solution is: $(-1, 2, -2)$
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