Here we have this function f(5)
Suppose the original function was f(x).
Now if we have to find the value of the function f(x) when we are given x=5, then we replace the x by 5.
So the function becomes f(5) at x=5.
For example:
If we have a function,
[tex]f(x) = 7x+9[/tex]
and we are to find value of this function at x=2,
then we replace the x by 2 everywhere in the function,
[tex]f(2) = 7(2)+9[/tex]
So this is how it works.
Answer: When a problem asks for f(5), it is asking for value of the function f(x) when x=5. Option A. is correct choice.
