From the diagram, Vertex =(2,3)
So, (h,k)=(2,3)
So, h=2 and k=3
The equation of parabola is
[tex] (x-h)^{2}=4p(y-k) [/tex]
p is the distance of directrix or focus from vertex.
As directrix is
y=8=k-p=3-p
So, 8=3-p
Let, us subtract 3 from both sides, we get
8-3=3-3-p
5=-p
or p=-5
So, h=2,k=3 and p=-5
So, the equation of parabola is
[tex] (x-2)^{2} [/tex]=4(-5)(y-3)
Equation of graph is
(x-2)^2=-20(y-3)