Question 658020
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Hi,
Note: vertex form of a Parabola opening up(a>0) or down(a<0), {{{y=a(x-h)^2 +k}}} 
where(h,k) is the vertex  and  x = h  is the Line of Symmetry
The standard form is {{{(x -h)^2 = 4p(y -k)}}}, where  the focus is (h,k + p)
{{{x^2=12y}}} ,  V(0,0), 4p = 12,  p = 3, F(0,3) and directrix is y = -3
{{{drawing(300,300,   -6, 6, -6, 6, grid(1),
circle(0,3,0.3),
circle(0,0,0.3),
graph( 300, 300, -6, 6, -6, 6,0, -3, x^2/12))}}}