Answer
$X=\left[ \begin{matrix}
7 & 27 \\
-8 & 36 \\
-17 & -4 \\
\end{matrix} \right]$
Work Step by Step
Consider the matrix equation, $B-X=4A$.
This implies that, $X=B-4A$ or $X=B-4A$.
Now we will consider,
$\begin{align}
& X=B-4A \\
& =\left[ \begin{matrix}
-5 & -1 \\
0 & 0 \\
3 & -4 \\
\end{matrix} \right]-4\left[ \begin{matrix}
-3 & -7 \\
2 & -9 \\
5 & 0 \\
\end{matrix} \right] \\
& =\left[ \begin{matrix}
-5 & -1 \\
0 & 0 \\
3 & -4 \\
\end{matrix} \right]-\left[ \begin{matrix}
-12 & -28 \\
8 & -36 \\
20 & 0 \\
\end{matrix} \right] \\
& =\left[ \begin{matrix}
7 & 27 \\
-8 & 36 \\
-17 & -4 \\
\end{matrix} \right]
\end{align}$
