## Precalculus (6th Edition) Blitzer

Published by Pearson

# Chapter 8 - Section 8.5 - Determinants and Cramer's Rule - Exercise Set - Page 945: 7

#### Answer

$33$

#### Work Step by Step

The general formula to calculate the determinate of a $2 \times 2$ matrix which has 2 rows and 2 coulmns is $D=\begin{vmatrix}a&b\\c&d\end{vmatrix}=ad-bc$ Now, $D=\begin{vmatrix}-5&-1\\-2&-7\end{vmatrix}=35-2=33$

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