Point charges of -6 µC, 3.0 µC, and +6 µC are located along the x axis at x = -1.0 cm, x = 0, and x = +1.0 cm, respectively. Calculate the electric field at x = 3.0 cm. N/C Calculate the electric field at x = 15.0 cm. N/C Locate a point on the positive x axis where the magnitude of the electric field is zero.