2. Решите уравнение b - 5/14 b = 5 1/7.

Решение:

$$b - \frac{5}{14}b = 5 \frac{1}{7}$$

$$b(1 - \frac{5}{14}) = \frac{5 \cdot 7 + 1}{7}$$

$$b(\frac{14}{14} - \frac{5}{14}) = \frac{36}{7}$$

$$b \cdot \frac{9}{14} = \frac{36}{7}$$

$$b = \frac{36}{7} : \frac{9}{14}$$

$$b = \frac{36}{7} \cdot \frac{14}{9}$$

$$b = \frac{36 \cdot 14}{7 \cdot 9}$$

$$b = \frac{4 \cdot 9 \cdot 2 \cdot 7}{7 \cdot 9}$$

$$b = 4 \cdot 2$$

$$b = 8$$

Ответ: 8