Răspuns
Explicație pas cu pas:
[tex]A+B = AB+C\\\\AB +C= \begin{pmatrix}1&2\\ 1&0\end{pmatrix}\begin{pmatrix}b&b\\ 0&1\end{pmatrix}+\begin{pmatrix}1&0\\ 0&0\end{pmatrix}=\begin{pmatrix}b+1&b+2\\ b&b\end{pmatrix}\\\\A+B = \begin{pmatrix}1&2\\ 1&0\end{pmatrix}+\begin{pmatrix}b&b\\ 0&1\end{pmatrix}=\begin{pmatrix}1+b&2+b\\ 1&1\end{pmatrix}\\\\\begin{pmatrix}1+b&2+b\\ 1&1\end{pmatrix} = \begin{pmatrix}1+b&2+b\\ b&b\end{pmatrix}\\\\[/tex]
b = 1
