Выполните действия: a) $$(\frac{4}{9} + \frac{2}{9}) \cdot \frac{9}{13}$$; б) $$\frac{2}{3} \cdot (\frac{9}{8} - \frac{3}{1})$$; в) $$(\frac{2}{11} - \frac{1}{11}) \cdot \frac{11}{8}$$

a) $$(\frac{4}{9} + \frac{2}{9}) \cdot \frac{9}{13} = \frac{6}{9} \cdot \frac{9}{13} = \frac{6 \cdot 9}{9 \cdot 13} = \frac{6}{13}$$

б) $$\frac{2}{3} \cdot (\frac{9}{8} - \frac{3}{1}) = \frac{2}{3} \cdot (\frac{9}{8} - \frac{24}{8}) = \frac{2}{3} \cdot (\frac{-15}{8}) = \frac{2 \cdot (-15)}{3 \cdot 8} = \frac{1 \cdot (-5)}{1 \cdot 4} = -\frac{5}{4} = -1\frac{1}{4}$$

в) $$(\frac{2}{11} - \frac{1}{11}) \cdot \frac{11}{8} = \frac{1}{11} \cdot \frac{11}{8} = \frac{1 \cdot 11}{11 \cdot 8} = \frac{1}{8}$$

Ответ:

• а) $$\frac{6}{13}$$
• б) $$-1\frac{1}{4}$$
• в) $$\frac{1}{8}$$