Answer
$(y-4)^2=-4(x-4)$
Work Step by Step
Equation of a parabola with horizontal axis and vertex at $(h,k)$:
$(y-k)^2=4p(x-h)$
Vertex: $V(h,k)=V(4,4)$
$h=4$
$k=4$
$(y-4)^2=4p(x-4)$
Now, use the point $(0,0)$:
$(0-4)^2=4p(0-4)$
$16=-16p$
$p=-1$
Finally:
$(y-4)^2=4(-1)(x-4)$
$(y-4)^2=-4(x-4)$
