Matrices And Determinants

If \(A = \left[ {\matrix{ 3 & 2 & 4 \cr 1 & 2 & 1 \cr 3 & 2 & 6 \cr } } \right]\) and A\(_{ij}\) are cofactors of the elements a\(_{ij}\) of A, then \({a_{11}}{A_{11}} + {a_{12}}{A_{12}} + {a_{13}}{A_{13}}\) is equal to