Use image instead of Math object
Here are two suggestions:
1. Go to http://www.codecogs.com/latex/eqneditor.php
- Type in math expressions, use large font and high resolution to have better quality/resolution when the image is pasted
- Download image
- Paste image into doc
- Use Wikipedia Sandbox at http://en.wikipedia.org/wiki/Wikipedia:Sandbox
- Similarly, type in math expression using Wikipedia syntax, eg <math>a = x + y</math>
- Show the preview and right-click on the image to save it
- NB: Check http://en.wikipedia.org/wiki/Help:Displaying_a_formula for the syntax
- Contrary to the first suggestion, it's not possible to change resolution of Wikipedia rendered images
HTH
PS: I suppose a lot of OOO Math fans are going to hate me but please don't start flame war.