Answer:
3x³ + 12x² - 7x - 28
Step-by-step explanation:
(f • g)(x) = f(x) × g(x)
= (x + 4)(3x² - 7)
Each term in the second factor is multiplied by each term in the first factor, that is
x(3x² - 7) + 4(3x² - 7 ) ← distribute both parenthesis
= 3x³ - 7x + 12x² - 28
= 3x³ + 12x² - 7x - 28
