Let a point charge q1 = 25.2 uC be located at x = 0 and a charge q2 = 5.3 uC at x = 4 m, both on the x-axis. (a) At what point in the xy-plane (other than infinity) would the resultant electric force on a third point charge be zero? (b) Repeat question (a) with q2 = -8.4 uC.