Algebra and Trigonometry 10th Edition

Published by Cengage Learning
ISBN 10: 9781337271172
ISBN 13: 978-1-33727-117-2

Chapter 10 - 10.3 - The Inverse of a Square Matrix - 10.3 Exercises - Page 735: 53

Answer

$x_1= -1; x_2=3; x_3= 2$

Work Step by Step

A system of equations can be written in the form: $AX=B$ where $B= \begin{bmatrix} x \\ y \\ z \end{bmatrix}$ When there exists an inverse of a matrix, the following relationship is true: $A A^{-1} = I$ Thus, $X=A^{-1} B = \begin{bmatrix} 4&-1& 1 \\ 2 & 2 & 3 \\ 5 &-2& 6 \end{bmatrix} \begin{bmatrix} -5 \\ 10 \\ 1 \end{bmatrix} = \begin{bmatrix} -1 \\ 3 \\ 2 \end{bmatrix}$ So, $X= \begin{bmatrix} x_1 \\ x_2 \\ x_3 \end{bmatrix}= \begin{bmatrix} -1 \\ 3 \\ 2 \end{bmatrix}$ Therefore, $x_1= -1; x_2=3; x_3= 2$
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