Given f(x)=x+2f(x)=x+2 and g(x)=x-2g(x)=x−2 how do you find f(g(x))? Precalculus Functions Defined and Notation Function Composition 1 Answer sente May 3, 2016 f(g(x)) = xf(g(x))=x Explanation: f(g(x))f(g(x)) is denoting the composition of ff and gg. Just as how if we were applying ff to a number, we would substitute that number for each xx in f(x)f(x), as we are applying to ff to g(x)g(x), we substitute g(x)g(x) for each xx in f(x)f(x). f(g(x)) = g(x)+2 = (x-2)+2 = xf(g(x))=g(x)+2=(x−2)+2=x As a side note, because f(g(x)) = g(f(x)) = xf(g(x))=g(f(x))=x, we say that ff and gg are inverses of one another. Answer link Related questions What is function composition? What are some examples of function composition? What are some common mistakes students make with function composition? Is function composition associative? Is it always true that (f@g)(x) = (g@f)(x)(f∘g)(x)=(g∘f)(x)? If f(x) = x + 3f(x)=x+3 and g(x) = 2x - 7g(x)=2x−7, what is (f@g)(x)(f∘g)(x)? If f(x) = x^2f(x)=x2 and g(x) = x + 2g(x)=x+2, what is (f@g)(x)(f∘g)(x)? If f(x) = x^2f(x)=x2 and g(x) = x + 2g(x)=x+2, what is (g@f)(x)(g∘f)(x)? What is the domain of (f@g)(x)(f∘g)(x)? What is the domain of the composite function (g@f)(x)(g∘f)(x)? See all questions in Function Composition Impact of this question 1241 views around the world You can reuse this answer Creative Commons License