Let A and B be the (2 × 2) matrices
A=\left[\begin{array}{ll}1 & 3 \\2 & 4\end{array}\right] \quad \text { and } \quad B=\left[\begin{array}{ll}3 & -2 \\1 & -1\end{array}\right].
1. Use formula (8) to calculate A^{-1}, B^{-1}, \text { and }(A B)^{-1}.
2. Use Theorem 17, property 2, to calculate (A B)^{-1}.
3. Show that (A B)^{-1} \neq A^{-1} B^{-1}.