Answer
$$f(2) = 2(2) +1$$ $$f(2) = 5$$
Work Step by Step
The notation $f(x)$ does not mean $“f\:times\:x.”$ The notation describes the value of the function at $x$.
For example, consider the function $f(x) = 2x +1$. When evaluating at $x=2$, this means that the value $2$ must be substituted to all $x$ in the given function.
Thus,
$$f(2) = 2(2) +1$$ $$f(2) = 5$$
