How do you find $[fog](x)$ and $[gof](x)$ given $f(x)=x-4$ and $g(x)=3x^2$ ?

Question

11228 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-03-05T16:58:27

The answers are
$[fog] (x) =3x^2-4$
$[gof] (x)=3(x-4)^2$

This is a composition of functions

$f(x)=x-4$

$g(x)=3x^2$

$[fog] (x) =f(g(x))=f(3x^2)=3x^2-4$

$[gof] (x)=g(f(x))=g(x-4)=3(x-4)^2$

How do you find [fog](x)[fog](x) and [gof](x)[gof](x) given f(x)=x-4f(x)=x-4 and g(x)=3x^2g(x)=3x^2?