Помогите пожалуйста даю 30 баллов

А)
$\frac{3}{7} + ( - \frac{1}{14}) = \frac{6 - 1}{14} = \frac{5}{14}$
б)
$- \frac{1}{5} - \frac{1}{10} = \frac{ - 2 - 1}{10} = - \frac{3}{10}$
в)
$- \frac{7}{8} \times \frac{16}{21} = - \frac{2}{3}$
г)
$\frac{3}{5} \times ( - \frac{15}{2} ) = - \frac{9}{2} = - 4 \frac{1}{2}$
2.а. $\frac{1}{2} \times \frac{1}{3} - \frac{3}{4} \times \frac{2}{3} = \frac{1}{6} - \frac{1}{2} = \\ = \frac{1 - 3}{6}= -\frac{2}{6}$
б.
$\frac{1}{5} \times ( \frac{2}{3} - \frac{3}{4} ) \div \frac{1}{2} = \\ \frac{1}{5} \times ( - \frac{ 1}{12} ) \div \frac{1}{2} = -\frac{1}{60} \times \frac{2}{1} = -\frac{1}{30}$
3. а.
$x + ( - \frac{4}{5} ) = \frac{1}{10} \\ x = \frac{1}{10} + \frac{4}{5} \\ x = \frac{1 + 8}{10} \\ x = \frac{9}{10}$
б.
$- \frac{3}{8} \div y = \frac{1}{16} \\ y = \frac{1}{16} \times ( - \frac{8}{3} ) \\ y = - \frac{1}{6}$