Having trouble creating a PV formula

[loserkido07]

Principle $140,000
Rate 7.25%
Years 15
Payement 1,278.01

The answer to the PV function is 134,638.06

My teacher gave us the answer and she wants us to figure out the equation. I have been working on this for over 6 hours. Suggestions and help would be wonderful.

 

[Dave Patton]

consider =PMT(Rate/12,Term*12,-Principal,0,0)