equidistant points?

[speed4baseball]

verify that P= (1,-1) is the same distance from A= (5,1) as it is from B= (-1,3). it is customary to say that P is equidistant from A and B. find three more points that are equidistant from A and B. Can points equidistant from A and B be found in every quadrant?
^i dont understand what to do? or how to do it

 

[galactus]

Just use the distance formula to verify it is the same distance between (1,-1) and (5,1) and between (1,-1) and (-1,3).