# Equilibrium? What does this mean?

## Homework Statement

Two small beads having positive charges 3q and q are fixed at the opposite ends of a horizontal insulating rod, extending from the origin to the point D, a third small charged bead is free to slide on the rod at a distance x away from the origin (but shorter than D). Can the equilibrium be stable?

Now I broke it down to

0 = 3d2 - 6xd +2x2

Solving x = 0.951

The book said that it can be stable if it is positive. But wouldn't a negative charge also worked since

$$k\frac{3q*-q_{x}}{x^2} = k\frac{q*-q_{x}}{(d-x)^2}$$

Negative and both sides and hence they cancel?