Ответ:

  1. \(\sqrt{5^4\cdot3^2}=5^2\cdot3=25\cdot3=75\).
  2. \(\sqrt{7^4\cdot2^6}=7^2\cdot2^3=49\cdot8=392\).
  3. \(\sqrt{(-5)^6\cdot(0.1)^2}=5^3\cdot0.1=125\cdot0.1=12.5\).
  4. \(\sqrt{12^2\cdot3^4}=12\cdot3^2=12\cdot9=108\).

Ответ: 1) 75; 2) 392; 3) 12,5; 4) 108.