Which of these equations has no solution for x,y∈Zx, y \in \mathbb{Z}x,y∈Z?
x2+y2=6x^2 + y^2 = 6x2+y2=6
x2+y2=5x^2 + y^2 = 5x2+y2=5
x2+y2=8x^2 + y^2 = 8x2+y2=8
x2+y2=25x^2 + y^2 = 25x2+y2=25