Intermediate Algebra (6th Edition)

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

Chapter 4 - Cumulative Review - Page 253: 43

Answer

$(-4,2,-1)$

Work Step by Step

Given Equations, $3x-y+z=-15$ Equation $(1)$ $x+2y-z=1$ Equation $(2)$ $2x+3y-2z=0$ Equation $(3)$ Add Equation $(1)$ and Equation $(2)$ $3x-y+z+x+2y-z=-15+1$ $4x+y=-14$ Equation $(4)$ Multiply Equation $(1)$ by $2$ and add with Equation $(3)$ $2(3x-y+z)+2x+3y-2z=2(-15)+0$ $6x-2y+2z+2x+3y-2z=-30$ $8x+y=-30$ Equation $(5)$ Subtract Equation $(4)$ from Equation $(5)$ $8x+y-(4x+y)=-30-(-14)$ $8x+y-4x-y=-30+14$ $4x=-16$ $x=-4$ Substituting $x$ value in Equation $(5)$ $8x+y=-30$ $8(-4)+y=-30$ $-32+y=-30$ $y=-30+32$ $y=2$ Substituting $x$and $y$ value in Equation $(1)$ $3x-y+z=-15$ $3(-4)-(2)+z=-15$ $-12-2+z=-15$ $-14+z=-15$ $z=-15+14$ $z=-1$ Solution $(-4,2,-1)$
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