$\{\begin{array}{l}\frac{-x-5}{2}=x-y\mid \cdot 2\\ 5-2\left(x-3\left(y-1\right)\right)=0\end{array}$  

$\{\begin{array}{l}-x-5=2x-2y\mid -2x+2y+5\\ 5-2\left(x-3y+3\right)=0\end{array}$      

$\{\begin{array}{l}-3x+2y=5\\ 5-2x+6y-6=0\mid +1\end{array}$  

$\{\begin{array}{l}-3x+2y=5\mid \cdot \left(-3\right)\\ -2x+6y=1\end{array}$  

$\{\begin{array}{l}9x-6y=-15\\ -2x+6y=1\end{array}$  

$\underline{}$  

$9x-2x-6y+6y=-15+1$  

$7x=-14\mid :7$  

$x=-2$  

Zatem otrzymujemy:

$\{\begin{array}{l}x=-2\\ -2\cdot \left(-2\right)+6y=1\end{array}$  

$\{\begin{array}{l}x=-2\\ 4+6y=1\mid -4\end{array}$  

$\{\begin{array}{l}x=-2\\ 6y=-3\mid :6\end{array}$  

$\{\begin{array}{l}x=-2\\ y=-\frac{1}{2}\end{array}$