Question

Let `f(x)=9x-8`, how do you find `(fof)(5)`?

Answer 1

Assuming you mean `f(5)`, then `f(5)=37`

Explanation:

If we have `f(x)` as some transformation applied to `x`, then `f(a)` will be the same transformation but applied to `a`.

So if `f(x)=2x^2+9`, then `f(a)=2a^2+9`. And if we say `a=5`, then `f(a)=2(5)^2+9=59`

So, using this principle, `f(5) = 9(5)-8=37`