A^{-1} = \left [
\begin{array}{c c c c}
1 & 0 & 0 & 0 \\
-2 & 1 & 0 & 0 \\
11 & -4 & 1 & 0 \\
-3 & 1 & 0 & 1 \\
\end{array} \right ]