According to the distance formula between two points: √ (x 2+y 2) = 2 √ [(x-3) 2+y 2].

Square of both sides: (x 2+y 2) = 4 [(x-3) 2+y 2].

Sorted: x 2-8x+y 2+ 12 = 0.

Formula: (x-4) 2+y 2 = 4.

The trajectory is a circle with point (4,0) as the center and 2 as the radius.