a) 3 3/7+1 3/14⋅(8 3/5-1 3/5);

a) Выполним действия по порядку.

1. $$8\frac{3}{5}-1\frac{3}{5} = 7$$
2. $$1\frac{3}{14} = \frac{14+3}{14} = \frac{17}{14}$$
3. $$\frac{17}{14} \cdot 7 = \frac{17 \cdot 7}{14} = \frac{17 \cdot 1}{2} = \frac{17}{2} = 8\frac{1}{2}$$
4. $$3\frac{3}{7} = \frac{3 \cdot 7 + 3}{7} = \frac{21+3}{7} = \frac{24}{7}$$
5. $$8\frac{1}{2} = \frac{8 \cdot 2 + 1}{2} = \frac{16+1}{2} = \frac{17}{2}$$
6. $$\frac{24}{7} + \frac{17}{2} = \frac{24 \cdot 2}{7 \cdot 2} + \frac{17 \cdot 7}{2 \cdot 7} = \frac{48}{14} + \frac{119}{14} = \frac{48+119}{14} = \frac{167}{14} = 11\frac{13}{14}$$

Ответ: $$11\frac{13}{14}$$