Let $\mathbf{A}=\left(\begin{array}{ccc}1 & 2 & 0 \\ -1 & 4 & -2 \\ 0 & 2 & 3\end{array}\right)$

Essay

Let $\mathbf{A}=\left(\begin{array}{ccc}1 & 2 & 0 \\ -1 & 4 & -2 \\ 0 & 2 & 3\end{array}\right)$ and $\mathbf{B}=\left(\begin{array}{ccc}4 & 3 & -2 \\ 0 & 4 & 0 \\ -1 & 1 & -1\end{array}\right)$
a) Find $\mathbf{A}+\mathbf{B}$
b) If $\vec{u}=(1,2,3)$ , find $\mathbf{A} \vec{u}$ .
c) If $\vec{v}=(-1,0,1)$ , find $\overrightarrow{\mathbf{B}} \vec{v}$ .