x2+y2−2y=4x^{2}+y^{2}-2 y=4x2+y2−2y=4
x2+y2−2y=0x^{2}+y^{2}-2 y=0x2+y2−2y=0
x2+y2+2y=0x^{2}+y^{2}+2 y=0x2+y2+2y=0
x2+y2−2y−3=0x^{2}+y^{2}-2 y-3=0x2+y2−2y−3=0
No Answer