Ответ:

  1. а) \(\frac{2}{\sqrt3}\cdot\frac{\sqrt3}{\sqrt3}=\frac{2\sqrt3}{3}\).
  2. в) \(\frac{1}{\sqrt5}\cdot\frac{\sqrt5}{\sqrt5}=\frac{\sqrt5}{5}\).
  3. д) \(\frac{5}{2\sqrt3}\cdot\frac{\sqrt3}{\sqrt3}=\frac{5\sqrt3}{6}\).
  4. ж) \(\frac{7}{3\sqrt7}\cdot\frac{\sqrt7}{\sqrt7}=\frac{7\sqrt7}{21}=\frac{\sqrt7}{3}\).

Ответ: а) \(\frac{2\sqrt3}{3}\); в) \(\frac{\sqrt5}{5}\); д) \(\frac{5\sqrt3}{6}\); ж) \(\frac{\sqrt7}{3}\).