Решение

1. а) $$rac{2x}{a} \cdot \frac{a}{8x} = \frac{2x \cdot a}{a \cdot 8x} = \frac{2ax}{8ax} = \frac{1}{4}$$
2. б) $$-\frac{3b}{2c} \cdot \frac{c}{9b} = -\frac{3b \cdot c}{2c \cdot 9b} = -\frac{3bc}{18bc} = -\frac{1}{6}$$
3. в) $$rac{m^2n}{15p} \cdot \frac{5p}{mn^2} = \frac{m^2n \cdot 5p}{15p \cdot mn^2} = \frac{5m^2np}{15m n^2 p} = \frac{m}{3n}$$
4. г) $$rac{35x^4}{18y^2} \cdot \frac{9y}{14x^2} = \frac{35x^4 \cdot 9y}{18y^2 \cdot 14x^2} = \frac{315x^4y}{252x^2y^2} = \frac{5x^2}{4y}$$
5. д) $$8b \cdot \frac{y}{4b^2} = \frac{8b}{1} \cdot \frac{y}{4b^2} = \frac{8b \cdot y}{1 \cdot 4b^2} = \frac{8by}{4b^2} = \frac{2y}{b}$$
6. е) $$rac{3a^2}{b^2} \cdot b^3 = \frac{3a^2}{b^2} \cdot \frac{b^3}{1} = \frac{3a^2 \cdot b^3}{b^2 \cdot 1} = \frac{3a^2b^3}{b^2} = 3a^2b$$

Ответ:

1. а) $$rac{1}{4}$$
2. б) $$-\frac{1}{6}$$
3. в) $$rac{m}{3n}$$
4. г) $$rac{5x^2}{4y}$$
5. д) $$rac{2y}{b}$$
6. е) $$3a^2b$$