Formulaic Maths Problems

Find $-4\begin{pmatrix} 2 & 4 \\ 5 & -7 \end{pmatrix} + \begin{pmatrix} -14 & 13 \\ -11 & 4 \end{pmatrix}$.

$\begin{pmatrix} \class{inputBox step1}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Ar0c0m0}}\hspace{35px}}~} & \class{inputBox step1}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Ar0c1m0}}\hspace{35px}}~} \\ \class{inputBox step1}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Ar1c0m0}}\hspace{35px}}~} & \class{inputBox step1}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Ar1c1m0}}\hspace{35px}}~} \end{pmatrix} + \begin{pmatrix} \class{inputBox step1}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Ar0c0m1}}\hspace{35px}}~} & \class{inputBox step1}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Ar0c1m1}}\hspace{35px}}~} \\ \class{inputBox step1}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Ar1c0m1}}\hspace{35px}}~} & \class{inputBox step1}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Ar1c1m1}}\hspace{35px}}~} \end{pmatrix}$ $\begin{pmatrix} [-8] & [-16] \\ [-20] & [28] \end{pmatrix} + \begin{pmatrix} [-14] & [13] \\ [-11] & [4] \end{pmatrix}$

$= \begin{pmatrix} \class{inputBox step2}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Br0c0}}\hspace{35px}}~} & \class{inputBox step2}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Br0c1}}\hspace{35px}}~} \\ \class{inputBox step2}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Br1c0}}\hspace{35px}}~} & \class{inputBox step2}{~\bbox[border:2px solid blue]{\strut\rlap{\class{inputReplace}{Br1c1}}\hspace{35px}}~} \end{pmatrix}$ $= \begin{pmatrix} [-22] & [-3] \\ [-31] & [32] \end{pmatrix}$