difference between rational and fraction

Question

my question is are we doing the same thing in $\frac{6}{-7}$ and $\frac{-6}{7}$? my argument is they are giving the same answer but at first we are dividing by $-7$ and second by $7$, so we are actually making changes to get the same answer, am I right? now fractions if only can have the denominator from the whole number set, then all fractions are rational but the converse is not true? again we can see the members in the set of rational and fractions are the same, but if the converse is not true can we say that both sets are the same? please help me to solve these 3 doubts