Ответ:

  1. \(\sqrt{72}=\sqrt{36\cdot2}=6\sqrt{2}\).
  2. \(\sqrt{0,98}=\sqrt{\frac{98}{100}}=\frac{\sqrt{98}}{10}=\frac{7\sqrt{2}}{10}\).
  3. \(-100\sqrt{0,08}=-100\sqrt{\frac{8}{100}}=-100\cdot\frac{2\sqrt{2}}{10}=-20\sqrt{2}\).

Ответ: 1) \(6\sqrt{2}\); 4) \(\frac{7\sqrt{2}}{10}\); 7) \(-20\sqrt{2}\).