Answer:
6x^2 - 2
Explanation:
plug in f(x) into the g(x) formula given
g(f(x)) = (3x)^2 + 1
simplify
= 9x^2+2
plug in g(x) into the f(x) formula given
f(g(x)) = 3(x^2+1)
distribute
= 3x^2 +3
set g(f(x)) - f(g(x))
(9x^2+2) - (3x^2+3)
carry the negative
9x^2+2-3x^2-3
simplify by combining like terms
6x^2-2