Решение

1) a)

$$0,2 : x = 1,2$$

$$x = \frac{0,2}{1,2} = \frac{2}{12} = \frac{1}{6}$$

1) б)

$$0,129 : x = 0,3$$

$$x = \frac{0,129}{0,3} = \frac{1,29}{3} = 0,43$$

2) a)

$$2,5 * x = 7,75$$

$$x = \frac{7,75}{2,5} = \frac{775}{250} = 3,1$$

2) б)

$$x * 0,14 = 0,4$$

$$x = \frac{0,4}{0,14} = \frac{40}{14} = \frac{20}{7}$$