How to Draw Intervals

I am writing up some exercises for students who are using College Algebra as their textbook. I need to know how to TeX pictures of intervals like those on page 3 and page 5 of the linked book. Thanks.

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Can you include the screenshot of an example here so that everybody who wonders what the question is about doesn't download the whole book for 1 page? –  percusse Jan 17 '13 at 17:16
@percusse It's two pages. Also, I don't know how to include a screenshot. –  Joe Johnson 126 Jan 17 '13 at 18:24
As is noted in the book's introduction, all LaTeX files used to created the book may be downloaded from the authors' website, stitz-zeager.com/Precalculus/…. –  Mico Jan 17 '13 at 18:24

There are many ways to do this. For example,

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{arrows}
\begin{document}
\tikz\draw [o-o] (0,0) -- +(1,0);
\tikz\draw [o-*] (0,0) -- +(1,0);
\tikz\draw [o->] (0,0) -- +(1,0);
\end{document}


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Thanks. One more question, how would I label the endpoints with numbers? –  Joe Johnson 126 Jan 17 '13 at 18:23
Try \tikz\draw [o-o] (0,0) node[pos=0, below] {$a$} -- +(1,0); –  Boris Jan 17 '13 at 18:33