Answer
$X=\left[\begin{array}{ll}
-8 & -8\\
2 & -9\\
8 & -4
\end{array}\right]$
Work Step by Step
Use the Properties of Matrix Addition (page 614)
$X-B=A$
... Add matrix B to both sides,
... $-B+B=0$, the zero matrix
$X+0=A+B$
$X=A+B$
$X=\left[\begin{array}{ll}
-3 & -7\\
2 & -9\\
5 & 0
\end{array}\right]+\left[\begin{array}{ll}
-5 & -1\\
0 & 0\\
3 & -4
\end{array}\right]$
$X=\left[\begin{array}{ll}
-8 & -8\\
2 & -9\\
8 & -4
\end{array}\right]$