3) \frac{5m}{12} - \frac{m}{8} = \frac{1}{3};

3) $$\frac{5m}{12} - \frac{m}{8} = \frac{1}{3}$$

Приведем дроби к общему знаменателю 24:

$$\frac{5m \cdot 2}{24} - \frac{m \cdot 3}{24} = \frac{1}{3}$$

$$\frac{10m - 3m}{24} = \frac{1}{3}$$

$$\frac{7m}{24} = \frac{1}{3}$$

$$7m = \frac{24}{3}$$

$$7m = 8$$

$$m = \frac{8}{7} = 1\frac{1}{7}$$

Ответ: $$m = 1\frac{1}{7}$$