Ответ:

  1. \(\sqrt{18}-\sqrt2+\sqrt{50}=3\sqrt2-\sqrt2+5\sqrt2=7\sqrt2\).
  2. \(\sqrt{24}+\sqrt{54}-\sqrt{96}=2\sqrt6+3\sqrt6-4\sqrt6=\sqrt6\).
  3. \(3\sqrt{50}-2\sqrt{18}+\sqrt8=15\sqrt2-6\sqrt2+2\sqrt2=11\sqrt2\).
  4. \((\sqrt{13}-2)(\sqrt{13}+2)=13-4=9\).
  5. \((\sqrt{13}+2\sqrt3)^2=13+4\cdot3+4\sqrt{39}=25+4\sqrt{39}\).
  6. \((3\sqrt2-\sqrt7)(3\sqrt2+\sqrt7)=18-7=11\).