Answer
$\left[\begin{array}{ll}
17 & 7\\
-5 & -11
\end{array}\right]$
Work Step by Step
$4B $ is a 2$\times$2 matrix
$-3C $ is a 2$\times$2 matrix
They can be added.
$4B+(-3C)=4B-3C=$
$=\left[\begin{array}{ll}
20 & 4\\
-8 & -8
\end{array}\right]+\left[\begin{array}{ll}
-3 & 3\\
3 & -3
\end{array}\right]$
$=\left[\begin{array}{ll}
17 & 7\\
-5 & -11
\end{array}\right]$
