Formulaic Maths Problems

Find $-3\begin{pmatrix} 8 & 3 \\ 2 & -9 \end{pmatrix} - \begin{pmatrix} -9 & 6 \\ 8 & 6 \end{pmatrix}$.

$\begin{pmatrix} \class{inputBox step1}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Ar0c0m0}}\hspace{35px}}~} & \class{inputBox step1}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Ar0c1m0}}\hspace{35px}}~} \\ \class{inputBox step1}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Ar1c0m0}}\hspace{35px}}~} & \class{inputBox step1}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Ar1c1m0}}\hspace{35px}}~} \end{pmatrix} + \begin{pmatrix} \class{inputBox step1}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Ar0c0m1}}\hspace{35px}}~} & \class{inputBox step1}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Ar0c1m1}}\hspace{35px}}~} \\ \class{inputBox step1}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Ar1c0m1}}\hspace{35px}}~} & \class{inputBox step1}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Ar1c1m1}}\hspace{35px}}~} \end{pmatrix}$ $\begin{pmatrix} [-24] & [-9] \\ [-6] & [27] \end{pmatrix} + \begin{pmatrix} [9] & [-6] \\ [-8] & [-6] \end{pmatrix}$

$= \begin{pmatrix} \class{inputBox step2}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Br0c0}}\hspace{35px}}~} & \class{inputBox step2}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Br0c1}}\hspace{35px}}~} \\ \class{inputBox step2}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Br1c0}}\hspace{35px}}~} & \class{inputBox step2}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Br1c1}}\hspace{35px}}~} \end{pmatrix}$ $= \begin{pmatrix} [-15] & [-15] \\ [-14] & [21] \end{pmatrix}$