Given . Compute (AB) – 1.
A = and B – 1 =
Here , (AB) – 1 = B – 1 A – 1
|A| = – 5 + 4 = – 1
Cofactors of A are:
C11 = – 1 C21 = 8 C31 = – 12
C12 = 0 C22 = 1 C32 = – 2
C13 = 1 C23 = – 10 C33 = 15
adj A =
=
So, adj A =
Now, A – 1 =
(AB) – 1 = B – 1 A – 1
=
Hence, =