## Algebra: A Combined Approach (4th Edition)

Given $f(x)$ and $g(x)$ 1. $(f o g)(x) = f(g(x))$ To find this, substitute the entire value of $g(x)$ for $x$ in $f(x)$. For instance, if $f(x) = x^2$ and $g(x) = 3x$, $(f o g)(x) = f(g(x)) = f(3x) = (3x)^2 = 9x^2$ 2. $(g o f)(x) = g(f(x))$ To find this, substitute the entire value of $f(x)$ for $x$ in $g(x)$. For instance, if $f(x) = x^2$ and $g(x) = 3x$, $(g o f)(x) = g(f(x)) = g(x^2) = 3(x^2) = 3x^2$
Given $f(x)$ and $g(x)$ 1. $(f o g)(x) = f(g(x))$ To find this, substitute the entire value of $g(x)$ for $x$ in $f(x)$. For instance, if $f(x) = x^2$ and $g(x) = 3x$, $(f o g)(x) = f(g(x)) = f(3x) = (3x)^2 = 9x^2$ 2. $(g o f)(x) = g(f(x))$ To find this, substitute the entire value of $f(x)$ for $x$ in $g(x)$. For instance, if $f(x) = x^2$ and $g(x) = 3x$, $(g o f)(x) = g(f(x)) = g(x^2) = 3(x^2) = 3x^2$