Help me factor this equation please ASAP

You sure you wrote it correctly? (ie neg sign after two of the exponent's ^). If you did, this is as good as it gets. Presuming it is correct, you might multiply and divide by (a^5c^4) to get a common den.

= [2c^6 - 5a^11 -a^9c^6 ]/ (a^5c^4)

But that's just as ugly