\left \{ {{2(x+1)-y=5} \atop {2(y-x)-2x=-6}} \right.
\left \{ {{2x+2-y=5} \atop {2y-2x-2x=-6}} \right.
\left \{ {{-y=5-2x-2} \atop {2y-4x=-6}} \right.
\left \{ {{-y=3-2x} \atop {2y-4x=-6}} \right.
\left \{ {{y=-3+2x} \atop {2y-4x=-6}} \right.
\left \{ {{y=-3+2x} \atop {2(-3+2x)-4x=-6}} \right.
\left \{ {{y=-3+2x} \atop {-6+4x-4x=-6}} \right.
\left \{ {{y=-3+2x} \atop {-6=-6}} \right.
układ nieoznaczony