Where is the voltage potential zero given two points?

Homework Statement

Two charges are fixed in place with a separation d. One charge is positive and has ten times (n = 10) the magnitude of the other charge, which is negative. The positive charge lies to the left of the negative charge, as in Figure 19.10. Relative to the negative charge, locate the two spots on the line through the charges where the total potential is zero relative to d.
Positive distance to the left of -q: ____ X d
Positive distance to the right of -q: _____ X d

V= kq/r

The Attempt at a Solution

0= k10q/(d-xd)+k-q/xd

That's about all I know, I'm sure we'll end up with a quadratic because there will be two spots where the potential = 0.

rock.freak667
Homework Helper

The Attempt at a Solution

0= k10q/(d-xd)+k-q/xd

Shouldn't this equation be

$$\frac{k 10q}{d-x} + \frac{-qk}{x}=0$$

I didn't really draw out the problem as I haven't done these questions in a few years.