Odpowiedź:
[tex]A=\left[\begin{array}{ccc}-2&4&1\\-1&2&4\end{array}\right][/tex]
[tex]A^T=\left[\begin{array}{ccc}-2&-1\\4&2\\1&4\end{array}\right][/tex]
[tex]B=\left[\begin{array}{ccc}2&-4\\-1&2\\\end{array}\right][/tex]
[tex]C=\left[\begin{array}{ccc}1&0\\0&1\\-2&0\end{array}\right][/tex]
[tex]A^TB=\left[\begin{array}{ccc}-2&-1\\4&2\\1&4\end{array}\right] \left[\begin{array}{ccc}2&-4\\-1&2\\\end{array}\right] =\left[\begin{array}{ccc}-4+1&8-2\\8-2&-16+4\\2-4&-4+8\end{array}\right] =\left[\begin{array}{ccc}-3&6\\6&-12\\-2&4\end{array}\right][/tex]
[tex]3C=3\left[\begin{array}{ccc}1&0\\0&1\\-2&0\end{array}\right] =\left[\begin{array}{ccc}3&0\\0&3\\-6&0\end{array}\right][/tex]
Stąd :
[tex]A^TB-3C=\left[\begin{array}{ccc}-3&6\\6&-12\\-2&4\end{array}\right] -\left[\begin{array}{ccc}3&0\\0&3\\-6&0\end{array}\right] =\left[\begin{array}{ccc}-6&6\\6&-15\\4&4\end{array}\right][/tex]
