ж) 1\frac{7}{12}:(-\frac{5}{12}+\frac{1}{4}); з) (-0,5+\frac{2}{3}):3,2.

ж) $$1\frac{7}{12}:(-\frac{5}{12}+\frac{1}{4}) = \frac{19}{12}:(-\frac{5}{12}+\frac{3}{12}) = \frac{19}{12}:(-\frac{2}{12}) = \frac{19}{12} \cdot (-\frac{12}{2}) = -\frac{19}{2} = -9,5$$

з) $$(-0,5+\frac{2}{3}):3,2 = (-\frac{1}{2} + \frac{2}{3}):\frac{32}{10} = (\frac{-3+4}{6}):\frac{16}{5} = \frac{1}{6} \cdot \frac{5}{16} = \frac{5}{96}$$

Ответ: ж) -9,5; з) 5/96