Ответ:

  1. \(\sqrt{2}\cdot\sqrt{18}=\sqrt{36}=6\).
  2. \(\sqrt{3}\cdot\sqrt{48}=\sqrt{144}=12\).
  3. \(\sqrt{13}\cdot\sqrt{52}=\sqrt{676}=26\).
  4. \(\sqrt{12}\cdot\sqrt{75}=\sqrt{900}=30\).
  5. \(\sqrt{17}\cdot\sqrt{2}\cdot\sqrt{34}=\sqrt{17\cdot2\cdot34}=\sqrt{1156}=34\).
  6. \(\sqrt{\frac{1}{11}}\cdot\sqrt{\frac{11}{13}}\cdot\sqrt{\frac{13}{25}}=\sqrt{\frac{1}{25}}=\frac{1}{5}\).
  7. \(\sqrt{\frac{3}{7}}\cdot\sqrt{3}\cdot\sqrt{\frac{1}{7}}=\sqrt{\frac{9}{49}}=\frac{3}{7}\).

Ответ: 1) 6; 2) 12; 3) 26; 4) 30; 5) 34; 6) \(\frac{1}{5}\); 7) \(\frac{3}{7}\).