The line is called the directrix. Here we have a vertical directrix, so a parabola sideways from usual.
Geometry is best done with squared distances. The squared distance from an arbitrary point (x,y) to the vertical line x=2 is
We equate that to the squared distance of (x,y) to the focus (-2,0):
We could call that done. A more standard form might be
Geometry is best done with squared distances. The squared distance from an arbitrary point (x,y) to the vertical line x=2 is
We equate that to the squared distance of (x,y) to the focus (-2,0):
We could call that done. A more standard form might be
