4. Сократите дробь 2n+2.21n+3 / 6n+1.7n+2.

4. Сократим дробь $$\frac{2^{n+2} \cdot 21^{n+3}}{6^{n+1} \cdot 7^{n+2}}$$.

$$\frac{2^{n+2} \cdot 21^{n+3}}{6^{n+1} \cdot 7^{n+2}} = \frac{2^{n+2} \cdot (3 \cdot 7)^{n+3}}{(2 \cdot 3)^{n+1} \cdot 7^{n+2}} = \frac{2^{n+2} \cdot 3^{n+3} \cdot 7^{n+3}}{2^{n+1} \cdot 3^{n+1} \cdot 7^{n+2}} = 2^{n+2-(n+1)} \cdot 3^{n+3-(n+1)} \cdot 7^{n+3-(n+2)} = 2^{n+2-n-1} \cdot 3^{n+3-n-1} \cdot 7^{n+3-n-2} = 2^1 \cdot 3^2 \cdot 7^1 = 2 \cdot 9 \cdot 7 = 126$$.

Ответ: 126