Question 316174
The y coordinate of the vertex is the midpoint of the line connecting the focus and perpendicular to the directrix.
Vy= (5+4)/2=4.5
Vertex:(-4,4.5)
Using the vertex form,
{{{y=a(x-(-4))^2+4.5}}}
{{{y=a(x+4)^2+4.5}}}
where {{{a}}} is any non-zero constant.

{{{ drawing( 300, 300, -8, 4, -2, 12,  grid(1), circle(-4,5,.15),
circle(-4,4.5,.15), blue(line(-10,4,12,4)),graph( 300, 300, -8, 4, -2, 12, (x+4)^2+4.5,3(x+4)^2+4.5)) }}}
Shown above are {{{a=1}}} in red and {{{a=3}}} in green.