Determine the value of $k$ for which the system $$\left\lbrace \begin{array}{r@{}r@{}r@{}r@{}r} x & + y & + 2 z & = & 3 \cr x & +2y & - 2 z & = & 0 \cr 4 x & +12 y & + k z & = & -11 \end{array} \right.$$
has no solutions.
$k=$