Question

If `f(x)=3x+4` and `g(x)=x^2-1`, how do you find `g(f(x))`?

Answer 1

I got: `g(f(x))=9x^2+24x+15`

Explanation:

Here you want the function `g` that has "inside" the Variable `f(x)`!
So we write the function `g` with instead of `x` the new variable `f(x)`:

`g(f(x))=(color(red)(3x+4))^2-1`

`g(f(x))=9x^2+24x+16-1`

`g(f(x))=9x^2+24x+15`