1) If the matrix A=[131−12−3012] then adj (adj A) is equal to A) A=[123612−1224−3601224] B) A=[1226−122436−36012−24] C) A=[12−123624−24−36012−24] D) none of these Answer: Option AExplanation:A=[131−12−3012] ⇒|A|=1.(4+3)−3(−2+0)+1(−1−0)=7+6−1=12 So, adj (adj A)= |A|n-2 =A =(12)3-2 A=12A =12[131−12−3012] =[123612−1224−3601224]