Here,
We have to find A-1 and
Firstly, we find the adj A and for that we have to find co-factors:
a11 (co – factor of 3) = (-1)1+1(2) = (-1)2(2) = 2
a12 (co – factor of -5) = (-1)1+2(-1) = (-1)3(-1) = 1
a21 (co – factor of -1) = (-1)2+1(-5) = (-1)3(-5) = 5
a22 (co – factor of 2) = (-1)2+2(3) = (-1)4(3) = 3
Now, adj A = Transpose of co-factor Matrix
Calculating |A|
= [3 × 2 – (-1) × (-5)]
= (6 – 5)
= 1
Ans.