There is not a difference if the negative sign is on the numerator or denominator.
Ex.
is basically -6 divided by 3
Just like in division, the negative sign wouldn't matter.
For -6/3 and 6/-3, both would by -2
For
, you can even write it as

In this form, the negative sign is just there the indicate the whole term is negative, not whether the numerator or denominator is negative, because it is not needed- it is the same either way.