10)(음+음)-=

10) $$\left(\frac{9}{17} + \frac{8}{17}\right) - \frac{5}{17} = \frac{9+8}{17} - \frac{5}{17} = \frac{17}{17} - \frac{5}{17} = \frac{17-5}{17} = \frac{12}{17}$$

Ответ: $$\frac{12}{17}$$