Find the inverse of each of the following matrices.
|A| =
= 1(6 – 1) – 2(4 – 3) + 3(2 – 9)
= 5 – 2 – 21
= – 18
Hence, A – 1 exists
Cofactors of A are:
C11 = 5 C21 = – 1 C31 = – 7
C12 = – 1 C22 = – 7 C32 = 5
C13 = – 7 C23 = 5 C33 = – 1
adj A =
=
So, adj A =
Now, A – 1 = .adj A
So, A – 1 = .
Hence, A – 1 =