2y2−x2xy\frac{2 y^{2}-x^{2}}{x y}xy2y2−x2
x2−2y2xy\frac{x^{2}-2 y^{2}}{x y}xyx2−2y2
x2−y2xy\frac{x^{2}-y^{2}}{x y}xyx2−y2