5) $$\frac{2}{9}m + \frac{4}{9}m - \frac{3}{9}m - \frac{5}{9}m = (\frac{2}{9} + \frac{4}{9} - \frac{3}{9} - \frac{5}{9})m = (\frac{2+4-3-5}{9})m = -\frac{2}{9}m$$
Ответ: -2/9m