Answer
$$\begin{pmatrix}11&-1\\ 10&1\end{pmatrix}$$
Work Step by Step
Using the rules of matrices in order to solve, we find:
$$\begin{pmatrix}5&-8\\ 12&20\end{pmatrix}+\begin{pmatrix}6&7\\ -2&-19\end{pmatrix}\\ \begin{pmatrix}5+6&\left(-8\right)+7\\ 12+\left(-2\right)&20+\left(-19\right)\end{pmatrix} \\ \begin{pmatrix}11&-1\\ 10&1\end{pmatrix}$$
