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

The sum is LaTeX: \displaystyle \left[\begin{matrix}21 & 11 & -58 & 5\\22 & 11 & 66 & -16\\17 & 5 & -28 & 5\\-39 & -13 & -24 & 28\end{matrix}\right] .