SOLUTION: Given f(x)=x^3 and g(x) = 3+6x^2, find (g o f) (x) Answers to choose from: (a) 3+6x^2/x^3 (b) 3+6x^2/x^3 (c) 3+6x^6 (d) 3+6x^2 Please help!

Algebra ->  College  -> Linear Algebra -> SOLUTION: Given f(x)=x^3 and g(x) = 3+6x^2, find (g o f) (x) Answers to choose from: (a) 3+6x^2/x^3 (b) 3+6x^2/x^3 (c) 3+6x^6 (d) 3+6x^2 Please help!      Log On


   



Question 29926: Given f(x)=x^3 and g(x) = 3+6x^2, find (g o f) (x)
Answers to choose from:
(a) 3+6x^2/x^3
(b) 3+6x^2/x^3
(c) 3+6x^6
(d) 3+6x^2
Please help!

Answer by sdmmadam@yahoo.com(530) About Me  (Show Source):
You can put this solution on YOUR website!
Given f(x)=x^3 ----(1)
and g(x) = 3+6x^2----(2)
(g o f)(x)
g(f(x))
= g(x^3) (using (1))
=g(t) where t = x^3
=3 + 6t^2 (using (2) )
=3 + 6[(x^3)^2]
=3+6(x^6) (using (a^m)^n = (a)^(mn) )
=3[1+2(x^6)]
which is your choice (c)