Ответ:
а) \(\frac{4}{9}\cdot\left(-\frac{3}{8}\right)=-\frac{12}{72}=-\frac{1}{6}\).
б) \(\frac{4}{9}:\frac{16}{21}=\frac{4}{9}\cdot\frac{21}{16}=\frac{7}{12}\).
Тогда \(\frac{5}{6}-\frac{7}{12}=\frac{10}{12}-\frac{7}{12}=\frac{3}{12}=\frac{1}{4}\).
Ответ: а) \(-\frac{1}{6}\); б) \(\frac{1}{4}\).
![Фото задания: а) \(\frac{4}{9}\cdot\left(-\frac{3}{8}\right)\); б) \(\left[\frac{5}{6}-\frac{4}{9}:\frac{16}{21}\right]\)](https://photoai.euroki.org/img_1790065832061.jpg)