## Precalculus (6th Edition) Blitzer

a) $A+B=\left[ \begin{matrix} 3 & 2 & 6 \\ 5 & 2 & -8 \\ -2 & 2 & 3 \\ \end{matrix} \right]$ b) $A+B=\left[ \begin{matrix} 3 & 2 & 6 \\ 5 & 2 & -8 \\ -2 & 2 & 3 \\ \end{matrix} \right]$ $A-B=\left[ \begin{matrix} 9 & -8 & 4 \\ 7 & -2 & 4 \\ -6 & 2 & -5 \\ \end{matrix} \right]$ c) $A+B=\left[ \begin{matrix} 3 & 2 & 6 \\ 5 & 2 & -8 \\ -2 & 2 & 3 \\ \end{matrix} \right]$ $\left( -4 \right)A=\left[ \begin{matrix} -24 & 12 & -20 \\ -24 & 0 & 8 \\ 16 & -8 & 4 \\ \end{matrix} \right]$ d) $3A+2B=\left[ \begin{matrix} 12 & 1 & 17 \\ 16 & 4 & -18 \\ -8 & 6 & 5 \\ \end{matrix} \right]$
(a) Perform the addition of the matrices $A$ and $B$ as below: \begin{align} & A+B=\left[ \begin{matrix} 6 & -3 & 5 \\ 6 & 0 & -2 \\ -4 & 2 & -1 \\ \end{matrix} \right]+\left[ \begin{matrix} -3 & 5 & 1 \\ -1 & 2 & -6 \\ 2 & 0 & 4 \\ \end{matrix} \right] \\ & =\left[ \begin{matrix} 3 & 2 & 6 \\ 5 & 2 & -8 \\ -2 & 2 & 3 \\ \end{matrix} \right] \end{align} (b) Perform the addition of the matrices $A$ and $B$ as below: \begin{align} & A-B=\left[ \begin{matrix} 6 & -3 & 5 \\ 6 & 0 & -2 \\ -4 & 2 & -1 \\ \end{matrix} \right]-\left[ \begin{matrix} -3 & 5 & 1 \\ -1 & 2 & -6 \\ 2 & 0 & 4 \\ \end{matrix} \right] \\ & =\left[ \begin{matrix} 9 & -8 & 4 \\ 7 & -2 & 4 \\ -6 & 2 & -5 \\ \end{matrix} \right] \end{align} (c) Perform the addition of the matrices $A$ and $B$ as below: \begin{align} & \left( -4 \right)A=\left( -4 \right)\left[ \begin{matrix} 6 & -3 & 5 \\ 6 & 0 & -2 \\ -4 & 2 & -1 \\ \end{matrix} \right] \\ & =\left[ \begin{matrix} -24 & 12 & -20 \\ -24 & 0 & 8 \\ 16 & -8 & 4 \\ \end{matrix} \right] \end{align} (d) Perform the addition of the matrices $A$ and $B$ as below: \begin{align} & 3A+2B=3\left[ \begin{matrix} 6 & -3 & 5 \\ 6 & 0 & -2 \\ -4 & 2 & -1 \\ \end{matrix} \right]+2\left[ \begin{matrix} -3 & 5 & 1 \\ -1 & 2 & -6 \\ 2 & 0 & 4 \\ \end{matrix} \right] \\ & =\left[ \begin{matrix} 18 & -9 & 15 \\ 18 & 0 & -6 \\ -12 & 6 & -3 \\ \end{matrix} \right]+\left[ \begin{matrix} -6 & 10 & 2 \\ -2 & 4 & -12 \\ 4 & 0 & 8 \\ \end{matrix} \right] \\ & =\left[ \begin{matrix} 12 & 1 & 17 \\ 16 & 4 & -18 \\ -8 & 6 & 5 \\ \end{matrix} \right] \end{align}