Ответ:

  1. \(\sqrt{(-3)^6}=\sqrt{729}=27\).
  2. \(\sqrt{2^2\cdot(-8)^2}=\sqrt{4\cdot64}=\sqrt{256}=16\).
  3. \(-3\sqrt{(-12)^4}=-3\cdot144=-432\).
  4. \(-\sqrt{5^2\cdot14^4}=-\sqrt{25\cdot38416}=-5\cdot196=-980\).