## Algebra and Trigonometry 10th Edition

Published by Cengage Learning

# Chapter 10 - Review Exercises - Page 762: 79

#### Answer

$x=36; y=11$

#### Work Step by Step

The system can be written as: $AX=B$ where, $B= \begin{bmatrix} x \\ y \end{bmatrix}$ Thus, $X=A^{-1} B = \begin{bmatrix} -1 & 4 \\ 2 & -7 \end{bmatrix} \begin{bmatrix} 8 \\ -5 \end{bmatrix} = \begin{bmatrix} (-1) (8)+(4)(-5) \\ (2) (8) +(-7)(-5) \end{bmatrix}=\begin{bmatrix} 36 \\ 11 \end{bmatrix}$ Thus, $X=A^{-1} B = \begin{bmatrix} -3 &2 \\ -2 & 1 \end{bmatrix} \begin{bmatrix} 4 \\ 2 \end{bmatrix} = \begin{bmatrix} (-3) (4)+(2)(2) \\ (-2) (4) +(1)(2) \end{bmatrix}=\begin{bmatrix} -8 \\ -6 \end{bmatrix}$ So, $X= \begin{bmatrix} x \\ y \end{bmatrix}=\begin{bmatrix} 36 \\ 11 \end{bmatrix}$ Therefore, $x=36; y=11$

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.