Ответ:

  1. \(\sqrt{1\frac{9}{16}}\cdot49=\sqrt{\frac{25}{16}}\cdot49=\frac54\cdot49=\frac{245}{4}\).
  2. \(\sqrt{\frac35}\cdot\sqrt{\frac{27}{5}}=\sqrt{\frac{81}{25}}=\frac95\).
  3. \(\sqrt{\frac{16\cdot1,69}{90000}}=\sqrt{\frac{27,04}{90000}}=\frac{5,2}{300}=\frac{13}{750}\).
  4. \(\frac{2\sqrt8}{\sqrt{392}}=\frac{4\sqrt2}{14\sqrt2}=\frac27\).
  5. \(\sqrt{8^4}=8^2=64\).
  6. \(\sqrt{(-4)^6}=\sqrt{4^6}=4^3=64\).

Ответ: 1) \(\frac{245}{4}\); 2) \(\frac95\); 3) \(\frac{13}{750}\); 4) \(\frac27\); 5) 64; 6) 64.