
\documentclass[14pt]{extarticle}
  \usepackage{lmodern}
  \usepackage{tikz}
  \pagestyle{empty}
  
\begin{document}
\begin{tikzpicture}
\path (0,0) node[inner sep=0pt] (sqrt) {\Huge$\displaystyle\sqrt{1} \quad \sqrt{-1}$} ;

\draw[line width=.2pt,blue] (sqrt.base west) -- (sqrt.base east) ;
\draw[line width=.2pt,green] ([yshift=.30ex]sqrt.south west) -- ([yshift=.30ex]sqrt.south east) ;
\draw[line width=.2pt,red] (sqrt.south west) -- (sqrt.south east) ;
\end{tikzpicture}
\end{document}
