Finding the domain and range

[Guest]

Can somebody help me and show me how to solve this please.
Let f(x) = [tex]\sqrt{x}[/tex] and g(x) = x - 3
a) Find the domain and range of f(x)
b) Find the domain and range of the composite function f o g(x) = f(g(x))
Thank you very much for helping .

[Guest]

The domain and range of $\sqrt{x}$ is [tex]x \ge 0[/tex]