14. $$\sqrt{\frac{16x^8}{y^6}} = \frac{\sqrt{16x^8}}{\sqrt{y^6}} = \frac{4x^4}{|y^3|}$$
При $$x=2$$ и $$y=4$$
$$\frac{4 \cdot 2^4}{|4^3|} = \frac{4 \cdot 16}{64} = \frac{64}{64} = 1$$
Ответ: 1