<p>I need to programmatically solve a system of linear equations in C, Objective C, or (if needed) C++.</p>

<p>Here's an example of the equations:</p>

<pre><code>-44.3940 = a * 50.0 + b * 37.0 + tx
-45.3049 = a * 43.0 + b * 39.0 + tx
-44.9594 = a * 52.0 + b * 41.0 + tx
</code></pre>

<p>From this, I'd like to get the best approximation for <code>a</code>, <code>b</code>, and <code>tx</code>.</p>

Are you looking for a software package that'll do the work or actually doing the matrix operations and such and do each step?
The the first, a coworker of mine just used
Ocaml GLPK
. It is just a wrapper for the
GLPK
, but it removes a lot of the steps of setting things up. It looks like you're going to have to stick with the GLPK, in C, though. For the latter, thanks to delicious for saving an old article I used to learn LP awhile back,
PDF
. If you need specific help setting up further, let us know and I'm sure, me or someone will wander back in and help, but, I think it's fairly straight forward from here. Good Luck!