[tex] 2B=2\cdot\left[\begin{array}{ccc}4&3\\-1&6\end{array}\right] =\left[\begin{array}{ccc}8&6\\-2&12\end{array}\right] \\----------------------\\A-2B-C=\left[\begin{array}{ccc}5&2\\3&0\end{array}\right] -\left[\begin{array}{ccc}8&6\\-2&12\end{array}\right]-\left[\begin{array}{ccc}2&8\\0&5\end{array}\right] \\\\=\left[\begin{array}{ccc}5-8-2&2-6-8\\3-(-2)-0&0-12-5\end{array}\right] =\left[\begin{array}{ccc}-5&-12\\5&-17\end{array}\right] [/tex]
