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

The sum is LaTeX: \displaystyle \left[\begin{matrix}-36 & -85 & 56 & 23\\1 & 59 & -41 & -86\end{matrix}\right] .