What expression is equivalent to (f g)(4)?

The expression ((f g)(4)) represents the product of the functions (f) and (g) evaluated at (4). This can be rewritten as (f(4) \cdot g(4)), meaning you first find the values of (f) and (g) at (4) and then multiply those two results together. Therefore, the equivalent expression is (f(4) \cdot g(4)).