г) $$(-4\frac{1}{2} +3\frac{3}{4}) \cdot (-9\frac{6}{7} +8\frac{4}{7})$$;

Решим пример по действиям:

1) $$-4\frac{1}{2} +3\frac{3}{4} = -4\frac{2}{4} +3\frac{3}{4} = -\frac{18}{4} + \frac{15}{4} = -\frac{3}{4}$$

2) $$-9\frac{6}{7} +8\frac{4}{7} = -9\frac{6}{7} +8\frac{4}{7} = -1\frac{2}{7} = -\frac{9}{7}$$

3) $$-\frac{3}{4} \cdot(-\frac{9}{7}) = \frac{3}{4} \cdot \frac{9}{7} = \frac{27}{28}

Ответ: $$\frac{27}{28}$$