б) $$4\frac{2}{7} \cdot 1\frac{2}{3} + \frac{5}{7} \cdot 1\frac{2}{3} = (4\frac{2}{7} + \frac{5}{7}) \cdot 1\frac{2}{3} = (4 + \frac{2}{7} + \frac{5}{7}) \cdot 1\frac{2}{3} = (4 + \frac{2+5}{7}) \cdot 1\frac{2}{3} = (4 + \frac{7}{7}) \cdot 1\frac{2}{3} = (4+1) \cdot 1\frac{2}{3} = 5 \cdot 1\frac{2}{3} = 5 \cdot \frac{1 \cdot 3 + 2}{3} = 5 \cdot \frac{5}{3} = \frac{5 \cdot 5}{3} = \frac{25}{3} = 8\frac{1}{3}$$
Ответ: $$8\frac{1}{3}$$