finding domain and range using graph

Question

I was given a graph of a quadratic function (parabola) and told to find the domain and range in INTERVAL notation. 

So lets say the vertex is (4,2) and there are no intercepts(?). I'm confused as what to do and how to write it. Here is an example of the graph if this helps: http://prntscr.com/ea4ylp

 

Would it be something such as : domain (2,6) but they would go on forever so wouldn't be it be infinite. I'm sorry i'm completely lost.

an answer or explanation ASAP if possible. Ty!

Answer 1

y =a(x-4)^2 +2

a>0

range = [2, infinity)

domain = (-infinity, infinity)