The coefficient matrix is
[tex]\begin{bmatrix}-1&-1&2\\3&2&-1\\4&4&-8\end{bmatrix}[/tex]
Its determinant is then
[tex]\det\begin{bmatrix}-1&-1&2\\3&2&-1\\4&4&-8\end{bmatrix}=-4\det\begin{bmatrix}-1&-1&2\\3&2&-1\\-1&-1&2\end{bmatrix}[/tex]
which is equal to 0.
