|A| = 1

Adj A =

A ^{– 1} =

B =

|B| = – 1

B ^{– 1} =

Also, AB =

=

|AB| = 407 – 406 = 1

And, adj(AB) =

(AB) ^{– 1} =

=

Now, B ^{– 1}A ^{– 1 =}

=

Hence, (AB) ^{– 1 =} B ^{– 1}A ^{– 1}