How do you find g(f(x))g(f(x)) if g(x) = x^2g(x)=x2 and f(x) = x + 3f(x)=x+3?

1 Answer
Mar 22, 2018

Replace all xx's in g(x)g(x) with the function f(x)f(x) to get
g( f(x) ) = ( x+3 )^2g(f(x))=(x+3)2

Explanation:

g(f(x))g(f(x)) means that you replace all xx's in g(x)g(x) with the function f(x)f(x). The easiest way to do this is rewrite g(x)g(x), replacing all xx's with a blank set of parenthesis, like this -

g( f(x) ) = ( )^2g(f(x))=()2

Now place the function f(x)f(x) into the parenthesis.

g( f(x) ) = ( x+3 )^2g(f(x))=(x+3)2