I think what is being asked here is to find the locus of points equidistant from the point (6,4.5) and the line
y=1.5,
The answer is a parabola with vertex (6,3) the equation of which is y=(x-6)2 + 3.
Why?
Because by (at least one) definition a parabola is the locus of points equidistant from a point and a line,