Ответ:

  1. \(\sqrt{\frac{36}{49\cdot121}}=\frac{\sqrt{36}}{\sqrt{49}\cdot\sqrt{121}}=\frac6{7\cdot11}=\frac6{77}\).
  2. \(\sqrt{\frac{100}{121}\cdot\frac4{81}}=\sqrt{\frac{400}{9801}}=\frac{20}{99}\).
  3. \(\sqrt{0.49\cdot81}-\sqrt{676\cdot0.16}=\sqrt{0.49}\cdot\sqrt{81}-\sqrt{676}\cdot\sqrt{0.16}=0.7\cdot9-26\cdot0.4=6.3-10.4=-4.1\).
  4. \(\frac{\sqrt{242}}{\sqrt2}+\frac{\sqrt{288}}{\sqrt2}=\sqrt{121}+\sqrt{144}=11+12=23\).

Ответ: а) \(\frac6{77}\); б) \(\frac{20}{99}\); в) −4,1; г) 23.