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, =