Compute all parts of given question:

Question: Point charges q1=+2.00 µC and q2=2.00 µC are placed at adjacent corners of a square for which the length of each side is 3.00cm. Point A is at the center of the square, and point B is at the empty corner closest to q2. Take the electric potential to be zero at a distance far from both charges.

Part I: What is the electric potential at point a due to q1 and q2?

Part II: What is the electric potential at point b?

Part III: A point charge q3 = -4.00 µC moves from point A to point B. How much work is done on q3 by the electric forces exerted by q1 and q2?

Please clarify the equations and steps are used to get the answer. Thanks!