б) \((8-5\frac{3}{4}) 2\frac{2}{3} + (8-6\frac{3}{5}) : 1\frac{3}{4}\);

Решение:

1. \(8-5\frac{3}{4} = 8 - \frac{23}{4} = \frac{32-23}{4} = \frac{9}{4}\)
2. \(\frac{9}{4} 2\frac{2}{3} = \frac{9}{4} \frac{8}{3} = \frac{9 8}{4 3} = \frac{72}{12} = 6\)
3. \(8-6\frac{3}{5} = 8 - \frac{33}{5} = \frac{40-33}{5} = \frac{7}{5}\)
4. \(1\frac{3}{4} = \frac{7}{4}\)
5. \(\frac{7}{5} : \frac{7}{4} = \frac{7}{5} \frac{4}{7} = \frac{4}{5}\)
6. \(6 + \frac{4}{5} = 6\frac{4}{5}\)

Ответ: 6\(\frac{4}{5}\)