$A\left( {\left[ \begin{gathered}
  \begin{array}{*{20}{c}}
  0&3 
\end{array} \hfill \\
  \begin{array}{*{20}{c}}
  { - 6}&{ - 1} 
\end{array} \hfill \\ 
\end{gathered}  \right] - \left[ \begin{gathered}
  \begin{array}{*{20}{c}}
  3&3 
\end{array} \hfill \\
  \begin{array}{*{20}{c}}
  { - 6}&2 
\end{array} \hfill \\ 
\end{gathered}  \right]} \right)B = A\left[ \begin{gathered}
  \begin{array}{*{20}{c}}
  { - 3}&0 
\end{array} \hfill \\
  \begin{array}{*{20}{c}}
  0&{ - 3} 
\end{array} \hfill \\ 
\end{gathered}  \right]B$

$ =  - 3AIB =  - 3AB = \left[ \begin{gathered}
  \begin{array}{*{20}{c}}
  { - 9}&{ - 6} 
\end{array} \hfill \\
  \begin{array}{*{20}{c}}
  { - \frac{3}{2}}&{ - 1} 
\end{array} \hfill \\ 
\end{gathered}  \right]$

$ \Rightarrow $ حاصل ضرب درایه‌های غیرواقع بر قطر اصلی $ = ( - 6)( - \frac{3}{2}) = 9$