2. a) $$2\frac{4}{13}\cdot(\frac{4}{5}-\frac{7}{12})-7:3\frac{1}{2} =$$ b) $$\frac{4}{3}+(-5\frac{1}{2}+\frac{5}{4}\cdot3\frac{1}{5}):\frac{9}{10} =$$

a) $$2\frac{4}{13} \cdot (\frac{4}{5} - \frac{7}{12}) - 7 : 3\frac{1}{2} = \frac{30}{13} \cdot (\frac{48}{60} - \frac{35}{60}) - 7 : \frac{7}{2} = \frac{30}{13} \cdot \frac{13}{60} - 7 \cdot \frac{2}{7} = \frac{1}{2} - 2 = \frac{1}{2} - \frac{4}{2} = -\frac{3}{2} = -1\frac{1}{2}$$

б) $$\frac{4}{3} + (-5\frac{1}{2} + \frac{5}{4} \cdot 3\frac{1}{5}) : \frac{9}{10} = \frac{4}{3} + (-\frac{11}{2} + \frac{5}{4} \cdot \frac{16}{5}) : \frac{9}{10} = \frac{4}{3} + (-\frac{11}{2} + \frac{4}{1}) : \frac{9}{10} = \frac{4}{3} + (-\frac{11}{2} + \frac{8}{2}) : \frac{9}{10} = \frac{4}{3} + (-\frac{3}{2}) : \frac{9}{10} = \frac{4}{3} + (-\frac{3}{2} \cdot \frac{10}{9}) = \frac{4}{3} + (-\frac{1}{1} \cdot \frac{5}{3}) = \frac{4}{3} - \frac{5}{3} = -\frac{1}{3}$$