\documentclass[12pt]{article}
\usepackage{amssymb,amsmath,amscd,concmath,amsfonts}
\usepackage{color}
\pagestyle{empty}
\begin{document}
\begin{equation*}
  p(s) = s^n + p_1 s^{n-1} + \cdots + p_{n-1} \underline{s} + p_n.
\end{equation*}
\end{document}