1 The matrices \(\mathbf { A }\) and \(\mathbf { B }\) are given by \(\mathbf { A } = \left( \begin{array} { l l } 2 & a
0 & 1 \end{array} \right)\) and \(\mathbf { B } = \left( \begin{array} { l l } 2 & a
4 & 1 \end{array} \right)\). I denotes the \(2 \times 2\) identity matrix. Find
- \(\mathbf { A } + 3 \mathbf { B } - 4 \mathbf { I }\),
- AB.