The co-factors of the elements of second column of [ array ccc 1 & -1 & 2 3 & 2 & 1 -1 & 3 & 4 array ] are

Step-by-step solution

Required cofactors are as follows: aligned & A ₁₂=(-1)¹⁺² | array cc 3 & 1 -1 & 4 array |=-(12+1)=-13 & ~A ₂₂=(-1)²⁺² | array cc 1 & 2 -1 & 4 array |=(4+2)=6 & ~A ₃₂=(-1)³⁺² | array cc 1 & 2 3 & 1 array |=-(-1-6)=5 aligned