8) $$- \frac{5}{6} : 1 \frac{2}{3} = - \frac{5}{6} : \frac{5}{3} = - \frac{5}{6} \cdot \frac{3}{5} = - \frac{5 \cdot 3}{6 \cdot 5} = - \frac{15}{30} = -\frac{1}{2}$$
Ответ: $$- \frac{1}{2}$$