Write a function that represents a parabola that opens upward and has a vertex of (9,11)

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.