Answer:
g(f(x)) = 9x² + 12x + 5
Step-by-step explanation:
g(f(x))
= g(3x + 2) ← substitute x = 3x + 2 into g(x)
= (3x + 2)² + 1
to expand (3x + 2)² = (3x + 2)(3x + 2)
each term in the second factor is multiplied by each term in the first factor
3x(3x + 2) + 2(3x + 2) ← distribute both parenthesis
= 9x² + 6x + 6x + 4 ← collect like terms
= 9x² + 12x + 4
then
g(f(x)) = (3x + 2)² + 1 = 9x² + 12x + 4 + 1 = 9x² + 12x + 5
