Solve: x+y=1,x2+y2=1x+y=1, x^2+y^2=1x+y=1,x2+y2=1.
(1,0),(0,1)(1, 0), (0, 1)(1,0),(0,1)
(1,0)(1, 0)(1,0) only
No solution
(0.5,0.5)(0.5, 0.5)(0.5,0.5)