Question

Consider the functions `f(x) = x^2-13` and `g(x) = x+5`. What is the value of `f[g(-4)]`?

Answer 1

`f(g(x))=-12`

Explanation:

`f(g(x)) =(x+5)^2-13`

put another way:

Let `g(x)=z=color(blue)(x+5)`

Then `f(z)=z^2-13 = (color(blue)(x+5))^2-13`

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
`f(g(-4))=(-4+5)^2-13`

`f(g(-4))=(+1)^2-13 = -12`