Find the adjoint of the given matrix and verify in each case that A. (adj A) = (adj A) =m |A|.I.

Here,


Now, we have to find adj A, and for that, we have to find co-factors:












Calculating A (adj A)






= 12I


Calculating (adj A)A






= 12I


Calculating |A|.I


Expanding along C1, we get




= [1(3 – 0) – (-1){9 – (-2)} + 2(0 – 1)]I


= [3 + 1(11) + 2(-1)] I


= (3 + 11 – 2 )I


= 12I


Thus, A(adj A) = (adj A)A = |A|I = 12I


A(adj A) = (adj A)A = |A|I


Hence Proved


Ans.


1