280 Сократи дроби: 1); 2) \frac{7^{4}}{7}; 3) \frac{a^{3}}{a^{6}} (a ∈ N); 4) \frac{b^{8}}{b^{4}} (b ∈ N).

1. $$1 = \frac{1}{1}$$
2. $$\frac{7^{4}}{7} = \frac{7^{4}}{7^{1}} = 7^{4-1} = 7^{3} = 7 \cdot 7 \cdot 7 = 49 \cdot 7 = 343$$
3. $$\frac{a^{3}}{a^{6}} = \frac{a^{3}}{a^{3} \cdot a^{3}} = \frac{1}{a^{3}}$$
4. $$\frac{b^{8}}{b^{4}} = \frac{b^{4} \cdot b^{4}}{b^{4}} = b^{4}$$

Ответ: 1) 1; 2) 343; 3) $$\frac{1}{a^{3}}$$; 4) $$b^{4}$$