If 
, then show that A – 3I = 2 (I + 3A – 1).
A = 
|A| = 4 – 10 = – 6 adj A = 
A – 1 = 
To Show: A – 3I = 2 (I + 3A – 1)
LHS A – 3I = 
= 
R.H.S 2 (I + 3A – 1) = 2I + 6A – 1 = 
= 
= 
Hence, A – 3I = 2 (I + 3A – 1)
13
If , then show that A – 3I = 2 (I + 3A – 1).
A =
|A| = 4 – 10 = – 6 adj A =
A – 1 =
To Show: A – 3I = 2 (I + 3A – 1)
LHS A – 3I =
=
R.H.S 2 (I + 3A – 1) = 2I + 6A – 1 =
=
=
Hence, A – 3I = 2 (I + 3A – 1)