Answer:
f(g(x)) = 9x^2 +12x -1
Step-by-step explanation:
f(g(x)) means you replace the x in f(x) with g(x), which is 3x + 1:
(3x+1)^2 + 2(3x+1) - 4
then expand and simplify:
(3x+1)(3x+1) + 6x+2 - 4
9x^2+6x+1 + 6x+2 - 4
and then collect all like terms:
9x^2
6x + 6x = 12x
1 + 2 - 4 = -1
