{x+4y=39
{2x-y=15
{2x+3y=2
{-2x+5y=-18
Х+4у=39. Х+4(2х-15)=39 =>х +8х-60=39 =>9х-60-39=0 =>9х=99 х=11 У=2х-15=> у=2•11-15 =>у=22-15 у=7