Answer :

Well first,

Rhizomes means: Rhizomes are the underground stems of higher plants (Angiosperms). The cells are differentiated into various tissues.

Rhizoids means: Rhizoids are undifferentiated multicellular structures of mosses and liverworts (Bryophytes). They are usually in direct contact with the ground. 

So, the difference is that Rhizomes are underground and are Angiosperms, and Rhizoids are in direct contact with the ground and are Bryophytes.

I know this because I looked in my science book and did research on it.

Hope I helped!

- Amber