## Algebra and Trigonometry 10th Edition

$130$
Our aim is to find the determinant of the matrix by expnading co-factors. The general form of a matrix of order $2 \times 2$ is: $|A|=\begin{bmatrix} p & q \\ r & s\end{bmatrix}=ps-qr$ and $|A|=4(-1)^3 \begin{bmatrix} -6 & 2 \\ 5 & 4 \end{bmatrix} +0+3 (-1)^5 \begin{bmatrix} -2 & 1 \\ -6 & 2 \end{bmatrix} =-4(-24-10)+0-3(-4+6)=130$