A parabola with the vertex of (5,4) and a focus of (8,4). What is the axis of symmetry?
recall that the parabola y^2 = 4px has
vertex at (0,0)
focus at (p,0)
So your parabola has p=3, with the vertex shifted to (5,4)
(y-4)^2 = 12(x-5)
see
https://www.wolframalpha.com/input/?i=parabola+%28y-4%29%5E2+%3D+12%28x-5%29