Answer
$\left[\begin{array}{ll}-3 & 13 \\ -8 & 27\end{array}\right]$
Work Step by Step
$A B=\left[\begin{array}{cc}5 & 4 \\ -2 & 3\end{array}\right],$ multiply equation with $B^{-1}$ from right $A B B^{-1}=\left[\begin{array}{cc}5 & 4 \\ -2 & 3\end{array}\right] B^{-1}$
$A=\left[\begin{array}{cc}5 & 4 \\ -2 & 3\end{array}\right] B^{-1}$
Inverse of $B$ :
$B^{-1}=\frac{1}{7-6}\left[\begin{array}{cc}1 & -3 \\ -2 & 7\end{array}\right]=\left[\begin{array}{cc}1 & -3 \\ -2 & 7\end{array}\right]$
$A=\left[\begin{array}{cc}5 & 4 \\ -2 & 3\end{array}\right] \cdot\left[\begin{array}{cc}1 & -3 \\ -2 & 7\end{array}\right]=\left[\begin{array}{cc}-3 & 13 \\ -8 & 27\end{array}\right]$
