Evaluate the expression $LaTeX: \displaystyle - 5 A - 2 B$
$LaTeX: A = \left[\begin{matrix}9 & 0 & 3 & 6\\6 & 5 & -1 & 4\\-1 & 8 & -7 & -1\end{matrix}\right], \text{ and } \quad\quad B = \left[\begin{matrix}-8 & -6 & 1 & 9\\8 & -9 & -2 & -6\\6 & 9 & 1 & -6\end{matrix}\right]$

The sum is $LaTeX: \displaystyle \left[\begin{matrix}-29 & 12 & -17 & -48\\-46 & -7 & 9 & -8\\-7 & -58 & 33 & 17\end{matrix}\right]$ .