Ответ:

[tex]AB=\left[\begin{array}{cc}3&1\\4&2\end{array}\right] *\left[\begin{array}{cc}1&-3\\2&1\end{array}\right] =\left[\begin{array}{cc}3*1+1*2&3*(-3)+1*1\\4*1+2*2&4*(-3)+2*1\end{array}\right]=...[/tex]

[tex]=\left[\begin{array}{cc}3*1+1*2&3*(-3)+1*1\\4*1+2*2&4*(-3)+2*1\end{array}\right]=\left[\begin{array}{cc}5&-8\\8&-10\end{array}\right][/tex]

[tex]BA=\left[\begin{array}{cc}1&-3\\2&1\end{array}\right]*\left[\begin{array}{cc}3&1\\4&2\end{array}\right] =\left[\begin{array}{cc}1*3+(-3)*4&1*1+(-3)*2\\2*3+1*4&2*1+1*2\end{array}\right]=...[/tex]

[tex]=\left[\begin{array}{cc}1*3+(-3)*4&1*1+(-3)*2\\2*3+1*4&2*1+1*2\end{array}\right]=\left[\begin{array}{cc}-9&-5\\10&4\end{array}\right][/tex]

Объяснение: