Answer
$X=\left[\begin{array}{ll}
29/2 & 25/2\\
-3 & 27/2\\
-27/2 & 8
\end{array}\right]$
Work Step by Step
$4B+3A=-2X$
Multiply both sides with $-\displaystyle \frac{1}{2} .$
$-\displaystyle \frac{1}{2}(4B+3A)=-\frac{1}{2}(-2X)$
$X=-\displaystyle \frac{1}{2}(4B+3A)$
$X=-\displaystyle \frac{1}{2}\cdot(4\left[\begin{array}{ll}
-5 & -1\\
0 & 0\\
3 & -4
\end{array}\right]+3\displaystyle \left[\begin{array}{ll}
-3 & -7\\
2 & -9\\
5 & 0
\end{array}\right])$
$X=-\displaystyle \frac{1}{2}\cdot(\left[\begin{array}{ll}
-20 & -4\\
0 & 0\\
12 & -16
\end{array}\right]+\displaystyle \left[\begin{array}{ll}
-9 & -21\\
6 & -27\\
15 & 0
\end{array}\right])$
$X=-\displaystyle \frac{1}{2}\cdot\left[\begin{array}{ll}
-29 & -25\\
6 & -27\\
27 & -16
\end{array}\right]$
$X=\left[\begin{array}{ll}
29/2 & 25/2\\
-3 & 27/2\\
-27/2 & 8
\end{array}\right]$
