b
(b) Let, $A = \left[ {\begin{array}{*{20}{c}}1&1&1\\1&2&{ - 3}\\2&{ - 1}&3\end{array}} \right]$; $adj(A) = \left[ {\begin{array}{*{20}{c}}{{A_{11}}}&{{A_{21}}}&{{A_{31}}}\\{{A_{12}}}&{{A_{22}}}&{{A_{32}}}\\{{A_{13}}}&{{A_{23}}}&{{A_{33}}}\end{array}} \right]$
$ \Rightarrow $ ${A_{11}} = 3,\,\,{A_{12}} = - 9,\,\,{A_{13}} = - 5$
${A_{21}} = - 4,\,{A_{22}} = 1,\,{A_{23}} = 3$
${A_{31}} = - 5,\,{A_{32}} = 4,\,{A_{33}} = 1$
$ \Rightarrow $ $Adj\,(A) = \left[ {\begin{array}{*{20}{c}}3&{ - 4}&{ - 5}\\{ - 9}&1&4\\{ - 5}&3&1\end{array}} \right]$.