Chapter 8 - Graphing Quadratic Functions - 8.4 - Graphing f(x) = a(x-h)^2 + k - Exercises - Page 446: 22

Vertex: $(-9,0)$. Axis of symmetry: $x=-9$

The quadratic function in the form $y=a(x-h)^2+k$ has the vertex $(h,k)$ and the axis of symmetry $x=h$. $$f(x)=-5(x+9)^2$$ Rewrite as: $$f(x)=-5(x-(-9)^2+0$$ Therefore $h=-9$, $k=0$. The vertex is: $$(h,k)=(-9,0).$$ The axis of symmetry is: $$x=-9.$$