X 2 2xy 2y 2 0
- X 2 2x y 2 2y 0
- X 2 2xy 2y 2 1 0
- X 2 2xy 2 dx x 3 3x 2y dy 0
- X 2 2y 2 2xy y 2 0
- X 2 2xy y 2 2x 2y 1 0
- X 2 2xy 2y 2 25 0
- X 2 2xy 2y 2 3x 0
- X 2 2xy 2y 2 2x 6y 5 0
- X 2 2xy 6x 6y 2y 2 8 0
- X 2 2xy 7 x y )+ 2y 2 10 0
- X 2 2y 2 2xy 3y 4 0
- X 2 2y 2 2xy 10y 25 0
- X 2y )( x 2 2xy 4y 2 )= 0
- X 2 2xy y 2 2x 2y 15 0
- 2xy dx x 2 2y 2 dy 0