-(p/q), -p/q and p/(-q) are all the same rational number when you simplify everything as much as possible. It doesn't matter if p and q are whole numbers or are fractions of whole numbers.
For example: Let p = 4 and q = 6. So this means -(p/q) = -4/6 = -2/3 and it also means -p/q = -4/6 = -2/3 and finally p/(-q) = 4/(-6) = -2/3. All three expressions reduce to -2/3.
