what is the answer to simplifying this equation:

Question

25a^-2 b^-5 c^8/40 a^5 c^9

Answer 1

(25a^-2 b^-5 c^8)/(40 a^5 c^9)

I made changes assuming that is what you meant.
= 5/(8a^7 b^5 c)

Usually, it is considered simplified if no negative exponents are hanging around.
check with your teacher what they consider "simplified"