Determining at which point the electric field is zero

[ughhphysics]

Homework Statement

Determine the point (other than infinity at which the electric field is zero.

There is a diagram that has 2 charged particles along the x-axis separated by a distance of 1.00m. The charged particle on the right is -2.50μC and the charged particle on the left is +6.00μC.

Homework Equations

The equation to be used is the one for Electric Fields: E=Ke(q/r2) r(hat)

The Attempt at a Solution

I understand how to use the Electric Field equations by plugging in all the values, but how do I determine the distance r in the equation. Where is the Electric field located in space?

 

[jennyjones]

The distance r in this equation is the distance between the two charges: 1.00 m
r(hat) is the direction.