I can't seem to figure out how to answer this problem! It's nothing i learned last year in pre-calc which is why i dont think it is pre-calc. but its in my math packet for next year's calc class...

A curve is traced by a point P(x,y) which moves such that its distance form the point A(-1,1) is three times its distance from the point B(2,-1). Determine the equation of the curve.