Ответ:

  1. При \(x=6, y=2\):
    \[\sqrt{\frac{36x^2}{y^4}}=\frac{6|x|}{y^2}=\frac{6\cdot6}{2^2}=\frac{36}{4}=9.\]
  2. При \(x=10, y=5\):
    \[\sqrt{\frac{25x^4}{y^6}}=\frac{5x^2}{|y|^3}=\frac{5\cdot100}{125}=4.\]
  3. При \(x=3, y=5\):
    \[\sqrt{\frac1{25}x^8y^2}=\frac{x^4|y|}{5}=\frac{81\cdot5}{5}=81.\]
  4. При \(x=7, y=3\):
    \[\sqrt{\frac1{9}x^2y^6}=\frac{|x|\,|y|^3}{3}=\frac{7\cdot27}{3}=63.\]

Ответ: 1) 9; 2) 4; 3) 81; 4) 63.