Ответ:

  1. \(\sqrt{18}=\sqrt{9\cdot2}=3\sqrt2\).
  2. \(\sqrt{40}=\sqrt{4\cdot10}=2\sqrt{10}\).
  3. \(\sqrt{50}=\sqrt{25\cdot2}=5\sqrt2\).
  4. \(\sqrt{48}=\sqrt{16\cdot3}=4\sqrt3\).
  5. \(\sqrt{243}=\sqrt{81\cdot3}=9\sqrt3\).
  6. \(\sqrt{675}=\sqrt{225\cdot3}=15\sqrt3\).

Ответ: 1) \(3\sqrt2\); 2) \(2\sqrt{10}\); 3) \(5\sqrt2\); 4) \(4\sqrt3\); 5) \(9\sqrt3\); 6) \(15\sqrt3\).