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

The sum is $LaTeX: \displaystyle \left[\begin{matrix}-7 & 34 & -58\\26 & -13 & 44\end{matrix}\right]$ .