Zero Electric Field on the x-Axis Due to Opposing Charges at Different Positions

[kimberlyann9]

Homework Statement

Charges q and -Q lie on the x-axis at x = 0 and x = d respectively. Charge -Q has a greater magnitude than q. In which region or regions on the x-axis is there a position where the electric field is zero?

A) x < 0
B) x < 0 and x > d
C) 0 < x < d and x > d
D) x > d
E) 0 < x < d

Homework Equations

E=kq/r^2

The Attempt at a Solution

Not too sure where to start...

 

[tiny-tim]

hi kimberlyann9!

Charges q and -Q lie on the x-axis at x = 0 and x = d respectively. Charge -Q has a greater magnitude than q. In which region or regions on the x-axis is there a position where the electric field is zero?
…
Not too sure where to start...

the electric field is zero if the total force on a charge is zero

we may as well assume the charge is positive

let's start with x > d …

how does the force from q compare with the force from Q, and are they in the same or opposite directions? ​