Electric Potential between two point charges

[ryanverbena]

Homework Statement

Two point charges Q1 = +5.00 nC and Q2 = −3.00 nC, are separated by 35.0 cm.
(a) What is the electric potential at a point midway between the charges?
(b) How much energy is required to bring an electron, located at infinity, to this midway
point?

Homework Equations

?

The Attempt at a Solution

PE = ke x q1q2/r

 

[Doc Al]

What's the formula for the electric potential at some distance from a point charge?