Question

How do you find `f(f(x))` if `f(x)=3x^2-5`?

Answer 1

`ff(x) = 9x^2-20`

Explanation:

When we evaluate a function using a certain argument (the thing which appears in the brackets), it means we replace every variable with that argument.

So for `f(x) = 3x^2-5`, `ff(x) = 3f(x) - 5 = 3(3x^2-5)-5 = 9x^2 - 20`