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

The sum is $LaTeX: \displaystyle \left[\begin{matrix}-57 & -56 & 43 & 77\\-24 & -71 & 23 & -39\end{matrix}\right]$ .