Since the directrix is vertical, use the equation of a parabola that opens up or down.
Find the vertex.
The vertex is halfway between the directrix and focus. Find the coordinate of the vertex using the formula . The coordinate will be the same as the coordinate of the focus.
Simplify the vertex.
Subtract from .
Move the negative in front of the fraction.
Find the distance from the focus to the vertex.
The distance from the focus to the vertex and from the vertex to the directrix is . Subtract the coordinate of the vertex from the coordinate of the focus to find .
To write as a fraction with a common denominator, multiply by .
Combine and .
Combine the numerators over the common denominator.
Simplify the numerator.
Multiply by .
Add and .
Substitute in the known values for the variables into the equation .
Find the Parabola with Focus (4,-3) and Directrix y=-6 (4,-3) y=-6