Answer
$AB^{-1}=\left[\begin{array}{c c} -7& -3& -4\\ 22/7& -2/7&16/7\\ 50/7&26/7&37/7\end{array} \right]$
Work Step by Step
Using a graphing calculator (see attached picture), we get:
$BAB^{-1}=\left[\begin{array}{c c} -7& -3& -4\\ 22/7& -2/7&16/7\\ 50/7&26/7&37/7\end{array} \right]$