8 The equations of three planes are
$$\begin{array} { r }
2 x + y + 3 z = 3
3 x - y - 2 z = 2
- 4 x + 3 y + 7 z = k
\end{array}$$
where \(k\) is a constant.
- By considering a suitable determinant, show that the planes do not meet at a single point.
- Given that the planes form a sheaf, determine the value of \(k\).