Electric Potential (I think I'm close?)

[Radanie]

Homework Statement

A -3.2 { nC} charge is on the x-axis at x_1 = -9 {cm} and a 14.6 {nC} charge is on the x-axis at x_2 = 16 {cm}.

***At what point or points on the y-axis is the electric potential zero?

Homework Equations

(1/4*pi*epsilon_0)*[(q1/r2) + (q2/r2)] = 0V

The Attempt at a Solution

The way I've tried solving it is by setting (q1/r2) = (q2/r2)
So 3.2*sqrt((16 cm)^2 + y^2) = 14.6*sqrt((-9 cm)^2 + y^2)
Eventually getting -14644.52 = 202.92 y^2
And y = +/- 8.5

Unfortunately this answer isn't being marked as correct. Does anyone see something wrong with the way I'm trying to solve this?

 

[confuted]

What happens when you square -9?

Hint: (y-y_0)^2