Problem: a charge +Q is located at the origin and a second charge, +4Q is at a distance d on the x-axis. where should a third charge, q, be placed, and what should be its sign and magnitude, so that all three charges will be in equilibrium. attempt: I don't know how to solve it fully, but my initial thought is to put the third charge in between the other two and give it a negative sign. The two other charges repel each other so i thought a negative one in the middle would put them in equilibrium. is this right?