A =

|A| = 3 + 6 – 8 = 1

Cofactors of A are:

C₁₁ = 1 C₂₁ = – 1 C₃₁ = 0

C₁₂ = – 2 C₂₂ = 3 C₃₂ = – 4

C₁₃ = – 2 C₂₃ = 3 C₃₃ = – 3

adj A =

=

So, adj A =

Now, A ^{– 1} =

Also, A² =

=

=

A³ = A².A =

=

Hence, A ^{– 1} = A³