Which of the following equations has infinitely many integer solutions?
x+y=1x + y = 1x+y=1
x2+y2=0x^2 + y^2 = 0x2+y2=0
x2+y2=1x^2 + y^2 = 1x2+y2=1
x2+y2=2x^2 + y^2 = 2x2+y2=2