Concept Used:A-1 = \(\frac{adj [A]}{|A|}\)Application:We have,\(A=\left( {\begin{array}{*{20}{c}} -2&1\\ 3&-1 \end{array}} \right)\)? |A| = (-2 × -1) - (3 × 1) = -1and, adj [A] = \(\left( {\begin{array}{*{20}{c}} -1&-1\\ -3&-2 \end{array}} \right)\)Hence, A-1 = \(\left( {\begin{array}{*{20}{c}} -1&-1\\ -3&-2 \end{array}} \right)\) × \(\frac{1}{-1}\) = \(\left( {\begin{array}{*{20}{c}} 1&1\\ 3&2 \end{array}} \right)\)Now, A + A-1 = \(\left( {\begin{array}{*{20}{c}} -2&1\\ 3&-1 \end{array}} \right)\) + \(\left( {\begin{array}{*{20}{c}} 1&1\\ 3&2 \end{array}} \right)\)Hence, A + A-1 = \(\left( {\begin{array}{*{20}{c}} -1&2\\ 6&1 \end{array}} \right)\)