$A^{\prime}=A$ and $B^{\prime}=B$ .......... $(1)$
Consider $(A B-B A)^{\prime} =(A B)^{\prime}-(B A)^{\prime}$ $[\because $ $=A^{\prime} -B^{\prime}] $
$=B^{\prime} A^{\prime}-A^{\prime} B^{\prime}$ $ [ \because $ $B^{\prime} A^{\prime}]$
$=B A-A B $ $[$ by $(1)$ $]$
$=-\,(A B-B A)$
$\therefore $ $(A B-A B)^{\prime} =-(A B-B A)$
Thus, $(A B-B A)$ is a skew-symmetric matrix.
વિધાન $1: $ $adj\left( {adj\;A} \right) = A$
વિધાન $2:$ $\left| {adj\;A} \right| = \left| A \right|$