7. Выполните действия: $$5 - (2,8 - \frac{2}{7} - \frac{9}{14}) \cdot 1,5$$

$$5 - (2.8 - \frac{4}{14} - \frac{9}{14}) \cdot 1.5 = 5 - (2.8 - \frac{13}{14}) \cdot 1.5$$
$$2.8 = \frac{28}{10} = \frac{14}{5}$$
$$5 - (\frac{14}{5} - \frac{13}{14}) \cdot 1.5 = 5 - (\frac{196 - 65}{70}) \cdot 1.5 = 5 - \frac{131}{70} \cdot 1.5 = 5 - \frac{131}{70} \cdot \frac{3}{2} = 5 - \frac{393}{140} = \frac{700 - 393}{140} = \frac{307}{140}$$