Вычислите.

\(5\sqrt{5}:\left(\dfrac14\sqrt{20}\right)=\) [ ]
\(\sqrt{\dfrac{-5⋅ 250}{-2}}=\) [ ]
\( \sqrt{6^6⋅\left(-12\right)^2}=\) [ ]
\(\sqrt{\dfrac{16^4⋅ (-7)^6}{(-14)^2}}=\) [ ]