If , prove that A – 1 = AT.

A = AT =


|A| = [ – 8(16 + 56) – 1(16 – 7) + 4( – 32 – 4)]


= – 81


Cofactors of A are:


C11 = 72 C21 = – 36 C31 = – 9


C12 = – 9 C22 = – 36 C32 = 72


C13 = – 36 C23 = – 63 C33 = – 36


adj A =


=


So, adj A =


Now, A – 1 =


Hence, A – 1 = = AT


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