1)

If the matrix  A=[131123012] then  adj (adj A) is equal to 


A) A=[12361212243601224]

B) A=[12261224363601224]

C) A=[12123624243601224]

D) none of these

Answer:

Option A

Explanation:

A=[131123012]

|A|=1.(4+3)3(2+0)+1(10)=7+61=12

 So, adj (adj A)= |A|n-2 =A

  =(12)3-2 A=12A

   =12[131123012]

 =[12361212243601224]