7. Вычислите (1 вариант)

a) \(\frac{2}{3} \cdot \frac{4}{7} : \frac{9}{14} = \frac{2}{3} \cdot \frac{4}{7} \cdot \frac{14}{9} = \frac{2 \cdot 4 \cdot 14}{3 \cdot 7 \cdot 9} = \frac{112}{189} = \frac{16}{27}\) б) \(\frac{18}{27} \cdot (\frac{1}{3})^2 + \frac{1}{9} = \frac{18}{27} \cdot \frac{1}{9} + \frac{1}{9} = \frac{18}{243} + \frac{1}{9} = \frac{2}{27} + \frac{3}{27} = \frac{5}{27}\)