Given F(x) and G(x), Find the Indicated Composition and State $f ( x ) = 5 x - 5$

Given f(x) and g(x) , find the indicated composition and state its domain.
-For $f ( x ) = 5 x - 5$ and $g ( x ) = 2 x + 5$ , what is the domain of $f \cdot g$ ?

A) $[ 0 , \infty )$
B) $( - \infty , \infty )$
C) $( 0 , \infty )$
D) $( - \infty , 0 )$