How Do You Determine Zero Potential Locations on the X-axis with Two Charges?

[zooboodoo]

Homework Statement

A charge of -1.9 × 10-9 C is at the origin and a charge of 9.4 × 10-9 C is on the x-axis at x = 3 m. At what two locations on the x-axis (xpositive, xnegative) is the potential zero?
xpositive = m
Xpositive = .5m
v=kq/x + (k(5Q/3-x))to solve for this value,
.5

xnegative = m
I'm lost on the second part of the problem which we need to calculate the X negative
If someone could help me set this equation up I would be very appreciative :)

Homework Equations

The Attempt at a Solution

 

[LowlyPion]

Careful.

How can the field be 0 on the line between a (+) and a (-) charge?