\documentclass[12pt]{article}
\usepackage{amssymb,amsmath,amscd,concmath,amsfonts}
\usepackage{color}
\pagestyle{empty}
\begin{document}
\begin{equation*}
  \lambda(s) = s^2 + (k_0 + k_1 + k_2) s + (k_0 k_2 + b_0 k_2 k).
\end{equation*}
\end{document}