Determinant of $$$\left[\begin{array}{cc}3 & -2\\1 & -1\end{array}\right]$$$

Calculate $$$\left|\begin{array}{cc}3 & -2\\1 & -1\end{array}\right|$$$.

The determinant of a 2x2 matrix is $$$\left|\begin{array}{cc}a & b\\c & d\end{array}\right| = a d - b c$$$.

$$$\left|\begin{array}{cc}3 & -2\\1 & -1\end{array}\right| = \left(3\right)\cdot \left(-1\right) - \left(-2\right)\cdot \left(1\right) = -1$$$

$$$\left|\begin{array}{cc}3 & -2\\1 & -1\end{array}\right| = -1$$$A