Question

If $A=\left[\begin{array}{ccc}5& 3& 8\\ 2& 0& 1\\ 1& 2& 3\end{array}\right]$. Write the cofactor of the element a₃₂.

Answer 1

Minor of a₃₂ = M₃₂ = $\left|\begin{array}{cc}5& 8\\ 2& 1\end{array}\right|=5-16=-11$

Cofactor of a₃₂ = A₃₂ = (−1)³⁺² M₃₂ = 11

Hence, the cofactor of the element a₃₂ is 11.