5. Решите уравнение: г) 14 : (2/9 x) = 5 : 2 1/7.

$$14 : (\frac{2}{9} x) = 5 : 2\frac{1}{7}$$

$$14 : (\frac{2}{9} x) = 5 : \frac{15}{7}$$

$$\frac{14}{\frac{2}{9}x} = \frac{5}{\frac{15}{7}}$$, $$\frac{14}{\frac{2}{9}x} = \frac{35}{15}$$

$$\frac{14}{\frac{2}{9}x} = \frac{7}{3}$$, $$\frac{2}{9}x = \frac{14 \cdot 3}{7}$$, $$\frac{2}{9}x = 2 \cdot 3$$, $$\frac{2}{9}x = 6$$

$$x = 6 : \frac{2}{9}$$, $$x = 6 \cdot \frac{9}{2}$$, $$x = 3 \cdot 9$$

$$x = 27$$

Ответ: 27.