Hi, I'm studying geometry and I'm stuck with this problem.

The problem says

"Two points, A and B, are given in the plane (no figure). Describe the set of points for which $\displaystyle {AX}^2-{BX}^2 $ is constant.

I am thinking that this triangle is isoceles and $\displaystyle AX^2 - BX^2 = 0$

but it sounds too easy of an answer maybe someone can explain this to me in terms of a geometric theory or whatever. Please explain with some reference to something..

Thanks!