16. Сократите дробь: в) 6t4.5t5 15t4;

в) $$ \frac{6t^4 \cdot 5t^5}{15t^4} = \frac{6 \cdot 5 \cdot t^4 \cdot t^5}{15t^4} = \frac{30 t^{4+5}}{15t^4} = \frac{30 t^9}{15t^4} = \frac{30}{15} \cdot \frac{t^9}{t^4} = 2t^{9-4} = 2t^5 $$

Ответ: $$2t^5$$