Two charges are placed on the x axis. One charge (q1 = +12.5 µC) is at x1 = +3.0 cm and the other (q2 = -13 µC) is at x2 = +9.0 cm. Find the net electric field (magnitude and direction) at the following locations. (a) x = 0 cm magnitude N/C direction (b) x = +6.0 cm magnitude N/C direction.