Three point charges are on the x axis: −9 μC at −3 m, 2 μC at the origin, and −5 μC at 3m.

Question

Find the force on the first charge. The value of the Coulomb constant is 8.98755 × 109 N · m2/C2.
Answer in units of N.

Answer 1

well the force from the - charge is opposite direction than the force from the + charge.

force12=(-k(-9)(2)/3^2)
force13=(-l)(-9)(-5)/6^2
notice I did not type 1e-12 in each numerator.

add the forces.