College Algebra 7th Edition

Published by Brooks Cole
ISBN 10: 1305115546
ISBN 13: 978-1-30511-554-5

Chapter 5, Systems of Equations and Inequalities - Section 5.2 - Systems of Linear Equations in Several Variables - 5.2 Exercises - Page 455: 23

Answer

$x=5,$ $y=0,$ $z=1$

Work Step by Step

$\begin{cases} x-4z=1\\ 2x-y-6z=4\\ 2x+3y-2z=8 \end{cases}$ Multiplying Equation 2 by -1 and adding it to Equation 3, results in new Equation 3. $\begin{cases} -2x+y+6z=-4\\ 2x+3y-2z=8\\ -- -- -- -- \\ 4y+4z=4 \end{cases}$ Multiplying Equation 1 by -2 and adding it to Equation 2, results in new Equation 2. $\begin{cases} -2x+8z=-2\\ 2x-y-6z=4\\ -- -- -- -- --\\ -y+2z=2 \end{cases}$ Multiplying new Equation 2 by 4 and adding it to new Equation 3. $\begin{cases} 4y+4z=4\\ -4y+8z=8\\ -- -- --\\ 12z=12 \end{cases}$ Thus, $z=1$. Substituting back into Equation 1, $x-4=1, x=5$. Substituting back into Equation 2, $10-y-6=4, y=0$
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