Fig. 4-3. The market equilibrium for the widget market.tex

\documentclass[12pt]{article}
\linespread{1.25}
\usepackage{times}

\usepackage{pgfplots}
\pgfplotsset{compat = newest}
\usetikzlibrary{positioning, arrows.meta}
\usepgfplotslibrary{fillbetween}
\usepackage{amsmath}

\begin{document}

\begin{center}
\begin{tikzpicture}
\begin{axis}[
scale = 1.2,
xmin = 0, xmax = 10.5,
ymin = 0.01, ymax = 10.5,
axis lines* = left,
xtick = {0,1,2,3,4,5,6,7,8,9,10},
ytick = {0,1,2,3,4,5,6,7,8,9,10},
grid = both,
minor tick num = 1,
grid style = solid,
minor grid style = dotted,
clip = false,
]
% Supply and demand curves
\addplot[color = blue, very thick] coordinates {(1, 9) (9, 1)};
\addplot[color = red, very thick] coordinates {(1, 1) (9, 9)};

% Dashed lines
\addplot[color = black, dashed, thick] coordinates {(0, 5) (5, 5) (5, 0)};

% Coordinate points
\addplot[color = black, mark = *, only marks, mark size = 3pt] coordinates {(5, 5)};

% Labels
\node [right] at (current axis.right of origin) {Widgets, $Q$};
\node [above] at (current axis.above origin) {Price, $P$};
\node [above = 5pt, fill = white] at (5, 5.2) {$E$};
\node [left = 10pt] at (0, 5) {$P_E$};
\node [below = 10pt] at (5, 0) {$Q_E$};
\node [right, fill = white] at (9, 1) {$D$};
\node [right, fill = white] at (9, 9) {$S$};
\end{axis}
\end{tikzpicture}
\end{center}
\textbf{Figure 4-3:} The market equilibrium for the widget market.

\end{document}