Answer:
3x³ + 3x² - 30x - 48
Explanation:
3(x + 2)(x² - x - 8) ← distribute (x + 2) by 3
= (3x + 6)(x² - x - 8)
each term in the second factor is multiplied by each term in the first factor
= 3x(x² - x - 8) + 6(x² - x - 8) ← distribute both parenthesis
= 3x³ - 3x² - 24x + 6x² - 6x - 48 ← collect like terms
= 3x³ + 3x² - 30x - 48