31) 36x²/y⁴ при х = 9 и у = 3;

31) $$\sqrt{\frac{36x^2}{y^4}}, x = 9, y = 3$$

$$\sqrt{\frac{36x^2}{y^4}} = \frac{6|x|}{y^2}$$

При $$x = 9, y = 3: \frac{6 \cdot 9}{3^2} = \frac{54}{9} = 6$$

Ответ: 6