x2+y2+4x=0x^{2}+y^{2}+4 x=0x2+y2+4x=0
x2+y2−4x=0x^{2}+y^{2}-4 x=0x2+y2−4x=0
2(x2+y2)−5x=02\left(x^{2}+y^{2}\right)-5 x=02(x2+y2)−5x=0
2(x2+y2)−3x=02\left(x^{2}+y^{2}\right)-3 x=02(x2+y2)−3x=0