x-y=7 xy=-12 1. x-y=7 x=7+y 2. (7+y)y=-12 7y+y^2+12=0 y^2+7y+12=0 по теореме виета: y1+y2=-7 y1*y2=12 y1=-4 y2=-3 3. x1=7+y1 x1= 3 x2=7+y2 x2=4 ответ: (3;-4) (4; -3)