Решение:
а) $-\frac{3}{5} * (-\frac{2}{5}) = \frac{3 * 2}{5 * 5} = \frac{6}{25}$;
б) $\frac{2}{3} * (-\frac{5}{7}) = -\frac{2 * 5}{3 * 7} = -\frac{10}{21}$;
в) $-\frac{3}{7} : (-\frac{4}{5}) = -\frac{3}{7} * (-\frac{5}{4}) = \frac{3 * 5}{7 * 4} = \frac{15}{28}$;
г) $\frac{3}{5} : (-\frac{2}{3}) = \frac{3}{5} * (-\frac{3}{2}) = -\frac{3 * 3}{5 * 2} = -\frac{9}{10}$;
д) $-\frac{15}{16} * (-\frac{48}{25}) = \frac{\overset{3}{\cancel{15}} * \overset{3}{\cancel{48}}}{\underset{1}{\cancel{16}} * \underset{5}{\cancel{25}}} = \frac{3 * 3}{1 * 5} = \frac{9}{5} = 1\frac{4}{5}$;
е) $-\frac{5}{3} : \frac{25}{27} = -\frac{5}{3} * \frac{27}{25} = -\frac{\overset{1}{\cancel{5}} * \overset{9}{\cancel{27}}}{\underset{1}{\cancel{3}} * \underset{5}{\cancel{25}}} = -\frac{1 * 9}{1 * 5} = -\frac{9}{5} = -1\frac{4}{5}$;
ж) $-\frac{3}{4} * (-\frac{4}{5}) = \frac{3 * \overset{1}{\cancel{4}}}{\underset{1}{\cancel{4}} * 5} = \frac{3 * 1}{1 * 5} = \frac{3}{5}$;
з) $-\frac{2}{3} : (-\frac{4}{5}) = -\frac{2}{3} * (-\frac{5}{4}) = \frac{\overset{1}{\cancel{2}} * 5}{3 * \underset{2}{\cancel{4}}} = \frac{1 * 5}{3 * 2} = \frac{5}{6}$.
Ответ:
а) $\frac{6}{25}$;
б) $-\frac{10}{21}$;
в) $\frac{15}{28}$;
г) $-\frac{9}{10}$;
д) $1\frac{4}{5}$;
е) $-1\frac{4}{5}$;
ж) $\frac{3}{5}$;
з) $\frac{5}{6}$.