Question

Three point charges are fixed on the x-axis: 2.9×10−6 C at x = −0.45 m, −9.3×10−6 C at the origin, and 9.1×10−6 C at x = 0.32 m. Find the electrostatic force acting on the charge at the origin due to the other two charges. Let a positive value indicate a force in the positive x direction, and a negative value indicate a force in the negative x direction.