How to calculate determinant of this matrix?
$\left[\begin{array}{cc} 1 & 2 \\ 0 & -2 \\ \end{array}\right]^3 . \left[\begin{array}{cc} 2 & 3 \\ -1 & 1 \\ \end{array}\right]^2-\left[\begin{array}{cc} 1 & 2 \\ 0 & -2 \\ \end{array}\right]^2 . \left[\begin{array}{cc} 2 & 3 \\ -1 & 1 \\ \end{array}\right]^3$
(It's an exam question, so please explain it.) Thanks..