How Do Point Charges Affect Force on a Charge Along the X-axis?

[wingit132]

Two point charges are located on the x axis: one charge q_1 = -15.0nC located at x_1 = -1.745m , and a second charge q_2 = 38.5nC at the origin.What is the total force along the x axis, including sign, exerted by these two charges on a third charge q_3 = 47.0nC placed between q_1 and q_2 at x_3 = -1.160m ? Use 8.85*10^-12 C^2/N*m^2 for the permittivity of free space.

I have set up the equations F_1 =q_1*q_3/4pi*e_0*r_1^2 and F_2 =q_2*q_3/4pi*e_0*r_2^2
q_1=-1.5*10^-8C
q_2=3.85*10^8C
q_3=4.7*10^8C
r_1=.585m
r_2=1.160m

It tells my I have the wrong answer but I just need a push in the right direction.

Thanks

 

[rl.bhat]

Hi wingit, welcome to PF.
Please show your calculations. Unless we see your calculations, we are not in a position to
say where you went wrong.