Whats the vertex point of f(x)=9(x-11)^2-3

Vertex point is (11, -3). You work it out by looking at the number inside the bracket to find the x-coordinate, it is always the negative of this. (so (x-11)² gives us x=11) and the y-coordinate is the number that has been added (or subtracted) at the end (y= -3).

I have added a sketch of the curve to help you visualise the vertex point. If you look at the lowest point (the minimum point) you'll see it has the coordinates (11, -3)