2. Given that
$$\mathbf { A } = \left( \begin{array} { r r r }
3 & 1 & - 2
- 1 & 0 & 5
\end{array} \right) \text { and } \mathbf { B } = \left( \begin{array} { r r }
2 & 4
- k & 2 k
3 & 0
\end{array} \right) , \text { where } k \text { is a constant }$$
- find the matrix \(\mathbf { A B }\),
- find the exact value of \(k\) for which \(\operatorname { det } ( \mathbf { A B } ) = 0\)