The function in vertex form is 
(refer to your other post I solved it there).
The general form of quadratic equations in vertex form is
, where (h, k) is the vertex of the parabola.
Here, a = 1, h = -6 and k = -54
Therefore, the vertex is (-6, -54) and it is a maximum because a = 1 is postive.
The general form of quadratic equations in vertex form is
Here, a = 1, h = -6 and k = -54
Therefore, the vertex is (-6, -54) and it is a maximum because a = 1 is postive.