What will be the overall fee and how to set up the equation. F (x) = 2x + 5

For whatever they give you for x, you substitute that with the 2 (x) + 5

Ex. if the x was 3 it would be 2 (3) + 5 and then the answer would be 11 since 3 times 2 is 6 and then 6+5=11