Answer
The minors are:
$M_{11}=5$
$M_{12}=0$
$M_{21}=2$
$M_{22}=-9$
The cofactors of the matrix A are:
$C_{11}=5$
$C_{12}=0$
$C_{21}=-2$
$C_{22}=-9$
Work Step by Step
$A=\begin{bmatrix}
-9 & 2 \\
0 & 5
\end{bmatrix}$
The minors are:
$M_{11}=5$
$M_{12}=0$
$M_{21}=2$
$M_{22}=-9$
The cofactors of the matrix A are:
$C_{11}=(-1)^{1+1}.5=5$
$C_{12}=(-1)^{1+2}.0=0$
$C_{21}=(-1)^{2+1}.2=-2$
$C_{22}=(-1)^{2+2}.(-9)=-9$
