4. A non-singular matrix \(\mathbf { M }\) is given by
$$\mathbf { M } = \left( \begin{array} { l l l }
3 & k & 0
k & 2 & 0
k & 0 & 1
\end{array} \right) \text {, where } k \text { is a constant. }$$
- Find, in terms of \(k\), the inverse of the matrix \(\mathbf { M }\).
The point \(A\) is mapped onto the point ( \(- 5,10,7\) ) by the transformation represented by the matrix
$$\left( \begin{array} { l l l }
3 & 1 & 0
1 & 2 & 0
1 & 0 & 1
\end{array} \right)$$ - Find the coordinates of the point \(A\).