Point charge 3.5 μc is located at x = 0, y = 0.30 m, point charge -3.5 μc is located at x = 0 y = -0.30 m. what are (a)the magnitude and (b)direction of the total electric force that these charges exert on a third point charge q = 4.5 μc at x = 0.40 m, y = 0?