Question

равны ли данные произведения?​

Answer 1

$E_1\cdot A_{12}=\left(\begin{array}{cc}1&0\\0&1\end{array}\right)\cdot \left(\begin{array}{cc}1&2\\3&4\end{array}\right)=\left(\begin{array}{cc}1&2\\3&4\end{array}\right)\\\\\\E_2\cdot A_{12}=\left(\begin{array}{cc}0&1\\1&0\end{array}\right)\cdot \left(\begin{array}{cc}1&2\\3&4\end{array}\right)=\left(\begin{array}{cc}3&4\\1&2\end{array}\right)\\\\\\E_1\cdot A_{12}\ne E_2\cdot A_{12}$