2 a³b 3c 15c a²b²

2) $$ \frac{a^3b}{15c} \cdot \frac{3c}{a^2b^2} = \frac{a^3b \cdot 3c}{15c \cdot a^2b^2} = \frac{3a^3bc}{15a^2b^2c} = \frac{3}{15} \cdot \frac{a^3}{a^2} \cdot \frac{b}{b^2} \cdot \frac{c}{c} = \frac{1}{5} \cdot a \cdot \frac{1}{b} \cdot 1 = \frac{a}{5b} $$

Ответ: $$\frac{a}{5b}$$