Ответ:
(x;y)=(0;-2)
Объяснение:
\left \{ {{x=2+y} \atop {x-2y=4}} \right. \\2+y-2y=4=>y=-2=>x=2-2=>x=0" alt="\left \{ {{x-y=2} \atop {x-2y=4}} \right. <=>\left \{ {{x=2+y} \atop {x-2y=4}} \right. \\2+y-2y=4=>y=-2=>x=2-2=>x=0" align="absmiddle" class="latex-formula">