Electric Potential Difference

Find the total potential energy this set of point charges contains.

Points A and B are in a region of uniform electric field, $\vec{E}$ = < 65, 0 > N/C. Point A is at < -0.1, 0 > and Point B is at < 0.7, 0 >. Find the electron potential difference between point A and B.

Points A and B are in a region of uniform electric field, $\vec{E}$ = < -85, 25 > N/C. Point A is at < -0.5, 0 > and Point B is at < 0.7, 0 >. Find the electron potential difference between point A and B.

A sphere carries a charge of +2 nC. Point A is X = 0.02 m to the direct right of the sphere, and point B is Y = 0.06 m to the right of the sphere. Find the electrostatic potential difference from A to B. (the solution involves calculus)