Answer
$\left[\begin{array}{ll}
-5 & -7\\
-1 & 9
\end{array}\right]$
Work Step by Step
$5C$ is a 2$\times$2 matrix
$-2B$ is a 2$\times$2 matrix
They can be added.
$5C-2B=5C+(-2B)=$
$=\left[\begin{array}{ll}
5 & -5\\
-5 & 5
\end{array}\right]+\left[\begin{array}{ll}
-10 & -2\\
4 & 4
\end{array}\right]$
$=\left[\begin{array}{ll}
-5 & -7\\
-1 & 9
\end{array}\right]$
