Chapter 9 Quadratic Relations and Conic Sections - 9.5 Graph and Write Equations of Hyperbolas - 9.5 Exercises - Mixed Review - Page 648: 45

$$\begin{pmatrix}10&7\\ -3&-6\end{pmatrix}$$

Adding the matrices by adding corresponding elements, we find: $$\begin{pmatrix}4+6&\left(-5\right)+12\\ 1+\left(-4\right)&\left(-2\right)+\left(-4\right)\end{pmatrix} \\ \begin{pmatrix}10&7\\ -3&-6\end{pmatrix}$$