решить это
x^2+y^2=200
xy=100

x^2+2xy+y^2=200+200(x+y)^2=400x+y=20xy=100x=20-y20y-y^2=100y^2-20y+100=0(y-10)^2=0y=10x=20-10=10x+y=-20xy=100x=-20-y-20y-y^2=100y^2+20y+100=0(y+10)^2=0y=-10x=-20+10=-10