Let A and B are square matrices of order 3 . If A = 4 , B = 6 , B = A - 2 I and a d j I - 2 A - 1 = k , then the value of k is equal to

Question

Let A and B are square matrices of order 3 . If A = 4 , B = 6 , B = A - 2 I and a d j I - 2 A - 1 = k , then the value of k is equal to,

MARKS App · Accepted Answer

B = A - 2 I Multiplying by A - 1 A - 1 B = I - 2 A - 1 … … . i a d j I - 2 A - 1 = I - 2 A - 1 2 = A - 1 B 2 = B 2 A 2 = 9 4 = 2.25