HELP!!!! Hard Physics Problem Involving Charges!!!?

Question

Two point charges are located on the x axis: one charge, q1= -16.0nC , is located at -1.685m ; the second charge, q2= 38.5nC , is at the origin .

What is the net force exerted by these two charges on a third charge q3 = 53.5nC placed between q1 and q2 at x3 at = -1.065m ?

Note that your answer may be positive or negative, depending on the direction of the force.

Use 8.85×10−12nC^2 / (N*m^2) for the permittivity of free space.

Thanks soooo much for your help!!! It's GREATLY appreciate!!!

Answer 1

Just use F=kQ1Q2/d^2 twice.

Once for q1 and q3 then again for q2 and q3

Get the directions correct.  The likes repell, of course.

Since the forces are in a line, add them linearly.  Draw a little picture to keep everything straight.

You'll do great!