If A = [ a _ ij ]_ 3 3 = [ array lll 1 & 2 & 3 1 & 1 & 5 2 & 4 & 7 array ] and Aij is a cofactor of a _ ij , then a₁₁ A₂₁+a₁₂ A₂₂+a₁₃ A₂₃ is equal to

Step-by-step solution

If we multiply elements of one row to the corresponding cofactors of another row and add them then we get zero hence, a₁₁ A₂₁+a₁₂ A₂₂+a₁₃ A₂₃=0