What is the vertex form of the equation of the parabola with a focus at (8,-5) and a directrix of #y=-6 #?
The directrix is a horizontal line, therefore, the vertex form is:
The focus is
The equation of the directrix is
Given that the focus is
Given that the equation of the directrix is
We can use equations  and  to find the values of k and f:
Use equation  to find the value of "a":
Substitute the values for, a, h, and k into equation :
Equation  is the desired equation.