Question: I want to create a presentation in Impress and need to embed a formula in text. I only found very old forum posts (over five years old), which said it is not possible.

Has this changed by now? How can I do it?

Answer: 
No, it is not possible to embed a formula or a graphical object in text in draw and impress.

In Libreoffice/Openoffice terms this would be called "anchoring the formula as a character". This is something that is possible in writer (contrary to one of the answers above).

TeXMaths is a great addition to Libreoffice, but can in no way help on this issue.

Unfortunately, this is a great deficiency that makes impress very very badly suited for any serious scientific presentation.

If you want to follow the state of this issue, look at <https://www.libreoffice.org/bugzilla/show_bug.cgi?id=35033>

If you want to support the addition of this feature to libreoffice, there is a bounty that you can contribute to at <http://www.freedomsponsors.org/core/issue/473/allow-inline-graphics-formulas-in-impress-and-draw>
With a current LO version, you can insert a formula quite easily usinng the menu: `Insert` -> `Object` -> `Formula`:

![Insert Formula](https://i.stack.imgur.com/iEoik.png)

By default, LO puts the formula in the center of the content area, so you may have to move and resize it manually. Double-clicking the formula will open LO Math again, so you can edit the formula afterwards, too.

EDIT:
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Maybe the [TexMaths extension](http://extensions.libreoffice.org/extension-center/texmaths-1) makes inserting formulae into Impress documents easier - i didn't test it. See also the [TexMaths homepage](http://roland65.free.fr/texmaths/).