4) 16b⁵ * 7c² / 8b¹⁰;

4) $$16b^5 \cdot \frac{7c^2}{8b^{10}} = \frac{16b^5 \cdot 7c^2}{8b^{10}} = \frac{16 \cdot 7 \cdot b^5 c^2}{8b^{10}} = \frac{2 \cdot 7 \cdot c^2}{b^{10-5}} = \frac{14c^2}{b^5}$$

Ответ: 14c²/b⁵