$$5 \frac{4}{18} + x - 2 \frac{4}{27}$$ при $$x = \frac{5}{6}$$ $$5 \frac{4}{18} + \frac{5}{6} - 2 \frac{4}{27} = 5 \frac{2}{9} + \frac{5}{6} - 2 \frac{4}{27} = 5 \frac{12}{54} + \frac{45}{54} - 2 \frac{8}{54} = 3 \frac{49}{54}$$
Ответ: $$3 \frac{49}{54}$$