\(\mathbf { 1 }\) You are given that \(\mathbf { A } = \left( \begin{array} { r r r } 2 & - 1 & 1
0 & p & - 4 \end{array} \right)\) and \(\mathbf { B } = \left( \begin{array} { r r } 0 & q
2 & - 2
1 & - 3 \end{array} \right)\).
- Find \(\mathbf { A B }\).
- Hence prove that matrix multiplication is not commutative.