## Algebra and Trigonometry 10th Edition

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The determinant of a $2 \times 2$ matrix can be computed by using the formula $det =ps-qr$ where $det =\begin{vmatrix}p & q \\r & s\end{vmatrix}$ Looking at row 3: $\begin{vmatrix} 1 & 4 &3 &2 \\-5 & 6&2&1\\0&0&0&0 \\ 3&-2& 1&5\end{vmatrix}=0-0+0-0=0$