2x2+2y2−9x=02 x^{2}+2 y^{2}-9 x=02x2+2y2−9x=0
2x2+2y2+9y=02 x^{2}+2 y^{2}+9 y=02x2+2y2+9y=0
3x2+3y2−10y=03 x^{2}+3 y^{2}-10 y=03x2+3y2−10y=0
3x2+3y2+15x=03 x^{2}+3 y^{2}+15 x=03x2+3y2+15x=0