Hey guys

A pt P(x,y) moves so that its distance from (3,4) is proportional to its distance from (-1,2). Find the equation of the locus of P if the origin is a pt on the locus.

I seriously have no clue how to do this q. - i tried using direct variation i.e.

...

then subbing k into

Naturally it didn't work =P

Help please?

Thanx a lot.