If I write your equations like this
eqs = {ue == 1 - uf,
Q == ue nte + uf ntf,
ntf == (dmq - pt)/g,
nte == xt/g}
and "forget" the xt - term (which is a complicated function of other (former?) pt's ) Reduce works giving lots of conditions.
Reduce[eqs, pt]
It is by no means clear what you want to do with your equations, which are really complicatedly written. You should avoid all these sub- and super-scripts
