7.4. Найдите значение выражения: a) -3,8|1:-19|; б) \(-\frac{1}{6}:\frac{7}{2}-\left|3,5\right|+\left|-\frac{1}{3}\right|\)

a) \(-3,8 \cdot |1 : (-19)| = -3,8 \cdot |-\frac{1}{19}| = -3,8 \cdot \frac{1}{19} = -\frac{3,8}{19} = -\frac{38}{190} = -\frac{1}{5} = -0,2\) б) \(-\frac{1}{6} : \frac{7}{2} - |3,5| + |-\frac{1}{3}| = -\frac{1}{6} \cdot \frac{2}{7} - 3,5 + \frac{1}{3} = -\frac{1}{21} - 3,5 + \frac{1}{3} = -\frac{1}{21} - \frac{35}{10} + \frac{1}{3} = -\frac{10}{210} - \frac{735}{210} + \frac{70}{210} = -\frac{675}{210} = -\frac{45}{14} = -3\frac{3}{14}\)