College Algebra (10th Edition)

Published by Pearson
ISBN 10: 0321979478
ISBN 13: 978-0-32197-947-6

Chapter 8 - Section 8.4 - Matrix Algebra - 8.4 Assess Your Understanding - Page 598: 55

Answer

$x=1/2, \ y=-1/2, \ z=1$ or $(1/2,-1/2,1)$

Work Step by Step

Writing the system in matrix form, $AX=B,$ the solution is $X=A^{-1}B$. Here, $A=\left[\begin{array}{rrr}{1}&{-1}&{1}\\{0}&{-2}&{1}\\{-2}&{-3}&{0}\end{array}\right]$, as in exercise 37. There, we found $A^{-1}=A^{-1}=\left[\begin{array}{rrr} {3}&{-3}&{1}\\ {-2}&{2}&{-1}\\ {-4}&{5}&{-2}\end{array}\right]$ With $B=\left[\begin{array}{l} 2\\ 2\\ 1/2 \end{array}\right]$, the solution, $X=A^{-1}B$ equals $X=\left[\begin{array}{l} 6-6+1/2\\ -4+4-1/2\\ -8+10-1 \end{array}\right]=\left[\begin{array}{l} 1/2\\ -1/2\\ 1 \end{array}\right]$ $x=1/2, \ y=-1/2, \ z=1$ or $(1/2,-1/2,1)$
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