Chapter 8 - Graphing Quadratic Functions - 8.4 - Graphing f(x) = a(x-h)^2 + k - Exercises - Page 447: 32

Vertex: $(3,6)$. Axis of symmetry: $x=3$

The quadratic function in the form $y=a(x-h)^2+k$ has the vertex $(h,k)$ and the axis of symmetry $x=h$. Given: $$f(x)=3(x-3)^2+6$$ Therefore $h=3$, $k=6$. The vertex is: $$(h,k)=(3,6).$$ The axis of symmetry is: $$x=3.$$