If , find (AT) – 1.

A =


Let B = AT =


|B| =


= ( – 1 – 8) – 0 – 2( – 8 + 3) = – 9 + 10 = 1


Cofactors of B are:


C11 = – 9 C21 = 8 C31 = – 5


C12 = – 8 C22 = 7 C32 = – 4


C13 = – 2 C23 = 2 C33 = – 1


adj B =


=


So, adj B =


Now, B – 1 =


Hence, (AT) – 1


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