How do you determine #f(g(x))# if #ƒ(x)=x(x + 1)# and #g(x)=x^2−1#? Precalculus Functions Defined and Notation Function Composition 1 Answer Gió Feb 4, 2015 As you can have, for example, #f(3)# where, in your function, you set #x=3# you can do the same here; the only difference is that you do not have a number but na entire function #g(x)=x^2-1# to substitute. You get: #f(g(x))=f(x^2-1)=(x^2-1)[(x^2-1)+1]=# #=(x^2-1)x^2=x^4-x^2# 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)#? If #f(x) = x + 3# and #g(x) = 2x - 7#, what is #(f@g)(x)#? If #f(x) = x^2# and #g(x) = x + 2#, what is #(f@g)(x)#? If #f(x) = x^2# and #g(x) = x + 2#, what is #(g@f)(x)#? What is the domain of #(f@g)(x)#? What is the domain of the composite function #(g@f)(x)#? See all questions in Function Composition Impact of this question 1738 views around the world You can reuse this answer Creative Commons License