I'm getting a huge output, but it appears that almost every term should actually be zero, unless I'm misunderstanding the expression.
For example, part of the output reads
a (0.25 + 0. b) + b^2 (0. + 0./c) + b (-1. + 0. c) - 0.5 c + (b (-1. b - 0.5 c) c)/a^2
FullSimplify won't get rid of these zero terms even with assumptions that
c are real and non-zero.