5. Вычислите: 2/3 : (-4/5)

\( \frac{2}{3}:\left(-\frac{4}{5}\right)=\frac{2}{3}\cdot\left(-\frac{5}{4}\right)=-\frac{10}{12}=-\frac{5}{6} \)

Ответ: \(-\frac{5}{6}\)