Answer
$X=\left[ \begin{matrix}
-8 & -8 \\
2 & -9 \\
8 & -4 \\
\end{matrix} \right]$
Work Step by Step
Consider the matrix equation, $X-B=A$
This implies that, $X=A+B$
Now add the matrix $A$ and $B$ as below:
$\begin{align}
& X=A+B \\
& =\left[ \begin{matrix}
-3 & -7 \\
2 & -9 \\
5 & 0 \\
\end{matrix} \right]+\left[ \begin{matrix}
-5 & -1 \\
0 & 0 \\
3 & -4 \\
\end{matrix} \right] \\
& =\left[ \begin{matrix}
-3+\left( -5 \right) & -7+\left( -1 \right) \\
2+0 & -9+0 \\
5+3 & 0-4 \\
\end{matrix} \right] \\
& =\left[ \begin{matrix}
-8 & -8 \\
2 & -9 \\
8 & -4 \\
\end{matrix} \right]
\end{align}$
