# Chapter 10 - 10.4 - The Determinant of a Square Matrix - 10.4 Exercises - Page 743: 49

$0$

#### Work Step by Step

The determinant of a $2 \times 2$ matrix can be computed by using the formula $det =ps-qr$ where $det =\begin{vmatrix}p & q \\r & s\end{vmatrix}$ $0 -1\begin{vmatrix} 2 & -1` \\4 & 2\end{vmatrix}+1 \begin{vmatrix} 2 &-1 \\ 4 & 2\end{vmatrix}=-[(4+4)+(4+4)]$ or, $=-8+8$ or, $=0$

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