\documentclass[12pt]{article}
\usepackage{pstricks}
\pagestyle{empty}
\textwidth=1.2\textwidth
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\begin{document}
{\LARGE$$y^2 = x^3 - x$$}
\begin{center}
\psset{unit=.75in}
\pspicture(-2,-5)(5,5)
\psgrid[gridcolor=gray]
\pscircle*[linecolor=red](-1,0){0.1}\rput(-1.5,0.2){$(-1,0)$}
\pscircle*[linecolor=red](1,0){0.1}\rput(1.5,0.2){$(1,0
)$}
\psline[linewidth=0.03]{->}(-2,0)(5,0)\rput(5.2,0){$x$}
\psline[linewidth=0.03]{->}(0,-5)(0,5)\rput(0,5.2){$y$}
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\endpspicture
\vspace{.5in}
Add $(-1,0)$ and $(1,0)$ together!
\end{center}
\end{document}