Question: A point charge q1 is held stationary at the origin. A second charge q2 is placed at point a and the electric potential energy of the pair of charges is +7.0 x 10-9 J. When the second charge is moved to point b, the electric force on the charge does -5.0 x 10-9 J of work.
Part A: What is the electric potential energy of the pair of charges when the second charge is at point b?
I want help to determine the electric potential energy of the pair of charges.