Two particles with charges +7e and -3e are initially very far apart (effectively an infinite distance apart). They are then fixed at positions that...

Two particles with charges +7e and -3e are initially very far apart (effectively an infinite distance apart). They are then fixed at positions that are 6.70 x 10-12 m apart. What is EPEfinal - EPEinitial,

which is the change in the electric potential energy?