Respuesta :

altavistard
vertex form of equation of parabola:

y-k = a(x-h)^2, where (h,k) is the vertex.  Here h=9 and k=11.

Then    y-11 = a(x-9)^2 or y = a(x-9)^2 + 11

If the coefficient of the (x-9)^2 term is 1, then     y = (x-9)^2 + 11.