Пошаговое объяснение:

[tex](2.8 \times a + \frac{35}{6} \times b) - \frac{72}{5} \times ( \frac{1}{6} \times a - \frac{5}{6} \times b ) = 2.8 \times a + \frac{35}{6} \times b - \frac{12}{5} \times a + 12 \times b = \frac{14}{5} \times a + \frac{107}{6} \times b - \frac{12}{5} \times a = \frac{2}{5} \times a + \frac{107}{6} \times b[/tex]