12. Вычислите: $$ -\frac{18}{25} : (3 - 2\frac{1}{5}) + 5\frac{5}{7} \cdot 1\frac{2}{5}$$

Решим пример по действиям: 1) $$3 - 2\frac{1}{5} = 3 - \frac{11}{5} = \frac{15}{5} - \frac{11}{5} = \frac{4}{5}$$ 2) $$-\frac{18}{25} : \frac{4}{5} = -\frac{18}{25} \cdot \frac{5}{4} = -\frac{18 \cdot 5}{25 \cdot 4} = -\frac{9 \cdot 1}{5 \cdot 2} = -\frac{9}{10}$$ 3) $$5\frac{5}{7} = \frac{5 \cdot 7 + 5}{7} = \frac{35 + 5}{7} = \frac{40}{7}$$ 4) $$1\frac{2}{5} = \frac{1 \cdot 5 + 2}{5} = \frac{5 + 2}{5} = \frac{7}{5}$$ 5) $$\frac{40}{7} \cdot \frac{7}{5} = \frac{40 \cdot 7}{7 \cdot 5} = \frac{8 \cdot 1}{1 \cdot 1} = 8$$ 6) $$-\frac{9}{10} + 8 = -\frac{9}{10} + \frac{80}{10} = \frac{71}{10} = 7\frac{1}{10}$$ Ответ: $$7\frac{1}{10}$$