\documentclass[a4paper, 12pt]{article}

% a nice font
\usepackage{kpfonts}

% basic text stuff
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}

\usepackage{tikz} % main tikz package

% for a nicer colorscheme
\input{colors.tex}

\begin{document}
    \begin{tikzpicture}[>=stealth', xscale=0.8]
        \draw[fill=brokengrey!20] (-1, -1.8) rectangle (9, 0);
        \draw[fill=red!90, domain=0:2, smooth, variable=\x, fill opacity=0.9]
         plot({1.5*\x}, {\x * (27.21 + \x * (-126.6 + \x * (229.9 + \x * (-200.7
          + \x * (84.24 - 13.61 * \x)))))}) -- (3.05, 0);
        \node[red] at (-0.2, 0.7) {$\mu$};
        \draw[fill=blue, fill opacity=0.9] plot[smooth] coordinates {
         (5, 0)  (5.1, -1.2)  (5.5, -1.2)
         (6, -0.8)  (6.4, -1.2) (6.9, -1.)
         (7.3, -1.3)  (7.7, -1)  (7.8, 0)};
        \node[blue!90] at (8, -1.2) {$\nu$};
        \draw[ultra thick, yellow] (0.65, 0) -- (0.65, 0.82);

        \draw[domain=0:2, smooth, variable=\x,]
         plot({1.5*\x}, {\x * (27.21 + \x * (-126.6 + \x * (229.9 + \x * (-200.7
          + \x * (84.24 - 13.61 * \x)))))}) -- (3.05, 0);

        \draw[ultra thick, yellow] (6., 0) -- (6., -0.8);
        \node[red!90] (x) at (0.65, -0.15) {$\bullet$};
        \node[blue!90] (y) at (6., 0.15) {$\bullet$};
        \node[below] at (x) {$x$};
        \node[above] at (y) {$y = \pi(x)$};
        \coordinate (y) at (5.9, 0.1);
        \draw[->, ultra thick, green, bend right=30]
         (x) edge node[below right=0.0 and -2.2 of x, black] {${\color{green}c}(x, \pi(x)){\color{red}\mu}(x)$} (y);
    \end{tikzpicture}
\end{document}