When dividing these, the powers are subtracted form each other.
We could split up the fraction into r's, s's, and t's.
r^-3 / r^2 = r^-5 [think of it as -3 -2]
s^5 / s = s^4
t^2 / t^-2 = t^4 [2 - - 2 = 4]
A negative power places it on the bottom of the fraction and the minus sign is removed from the power.
So the answer is A: (s^4)(t^4)/r^5
