(ii) A−1=[−25−257545310−451515−15]\boxed{A^{-1}=\begin{bmatrix}-\frac{2}{5}&-\frac{2}{5}&\frac{7}{5}\\\frac{4}{5}&\frac{3}{10}&-\frac{4}{5}\\\frac{1}{5}&\frac{1}{5}&-\frac{1}{5}\end{bmatrix}}A−1=−525451−521035157−54−51