linear algebra question..

[sonya]

Let P=(9,-7,-1) and Q=(-5,-5,-5). The set of all points that are equidistant from P and Q are given by the equation __x + __y + __z + __ = 0.

^^The question!

All I want to know is how to start this question. I thought I was supposed to find the equation of the normal to the center of PQ but that didnt work out. Thanks!

[Tom Mattson]

You need to set up the distance formula twice. Once for the distance between point P and the point (x,y,z) and once for the distance between point Q and the point (x,y,z). And since (x,y,z) is equidistant from P and Q, you do..........what?