Question

Даю 100
БАЛОВ СРОЧНООО

Answer 1

$\displaystyle \left \{ {{y-x=1} \atop {2y-x=4}} \right. \\\\\left \{ {{x=-1+y} \atop {2y-x=4}} \right. \\\\2y-(-1+y)=4\\y=3\\x=-1+3\\x=2\\(x,y)=(2,3)$