If I understand correctly, I use this formula $f(x)= a_0x^n + a_1x^{n-1} + a_2x^{n-2} + a_{n-2}x^2 + a_{n-1}x +a_n $ and assign the variable $x = 0$.
$f(0)=a_00^n + a_10^{n-1} + a_20^{n-2} + a_{n-2}0^2 + a_{n-1}0 + a_n$
Then I get this $f(0)=a_n $ But this is a free member of the polynomial.
I right solved ?
If the question is to find $f(0)$, then according to you formula, $$f(0)=a_n$$
This is Like when you have: $$g(x)=3x^{2}+5x+7$$
$$g(0)=3(0^{2})+5(0)+7=7$$