Please refer to quantitative review guid on exponents and roots theory.

It suffices to consider positive roots only when root values are not specified as opposed to e.g. \(x^2=16\) .. \(x=-4\) or \(x=+4\)

\(\sqrt{\frac{1}{16}}\) = \(+\frac{1}{4}\) only

It might be confusing, but if you refer to the guide, it'll be helpful what to consider!