Упростим выражение:
$$\frac{x^{\frac{1}{2}} y^{\frac{1}{4}} + 3 x^{\frac{1}{4}} y^{\frac{1}{2}}}{x^{\frac{1}{2}} + 6 x^{\frac{1}{4}} y^{\frac{1}{4}} + 9 y^{\frac{1}{2}}} = \frac{x^{\frac{1}{4}} y^{\frac{1}{4}} (x^{\frac{1}{4}} + 3 y^{\frac{1}{4}})}{(x^{\frac{1}{4}} + 3 y^{\frac{1}{4}})^2} = \frac{x^{\frac{1}{4}} y^{\frac{1}{4}}}{(x^{\frac{1}{4}} + 3 y^{\frac{1}{4}})}$$
Ответ: $$\frac{x^{\frac{1}{4}} y^{\frac{1}{4}}}{(x^{\frac{1}{4}} + 3 y^{\frac{1}{4}})}$$