25. \( \sqrt[\ell]{\frac{9}{25}} \)

To evaluate \( \sqrt[\ell]{\frac{9}{25}} \), we can simplify it into two parts. First, recognize that \( \frac{9}{25} \) can be expressed as \( \frac{3^2}{5^2} \). Now, using the property of roots, we can apply the exponent to both the numerator and the denominator giving us: \[ \sqrt[\ell]{\frac{9}{25}} = \frac{\sqrt[\ell]{9}}{\sqrt[\ell]{25}} = \frac{\sqrt[\ell]{3^2}}{\sqrt[\ell]{5^2}} = \frac{3^{\frac{2}{\ell}}}{5^{\frac{2}{\ell}}} = \left(\frac{3}{5}\right)^{\frac{2}{\ell}} \] Thus, the simplified result is \( \left(\frac{3}{5}\right)^{\frac{2}{\ell}} \).