Since the directrix is vertical, use the equation of a parabola that opens up or down.

The distance from the focus to the vertex and from the vertex to the directrix is . Subtract the value of the directrix from the coordinate of the vertex to find .

Subtract from .

Substitute in the known values for the variables into the equation .

Simplify.

Find the Parabola with Vertex f(3,8) and Directrix y=4 (3,8) y=4