Three point charges, +6.5 ¦ÌC, +1.4 ¦ÌC, and

Question

−3.9 ¦ÌC, lie along the x-axis at 0 cm, 1.8 cm,
and 5.3 cm, respectively.
What is the force exerted on q1 by the other
two charges? (To the right is positive.) The
Coulomb constant is 8.99 ¡Á 109 N ¡¤ m2/C2.
Answer in units of N