Answer:
x³ - 12x² + 43x - 40
Explanation:
f(x) × g(x)
= (x - 5)(x² - 7x + 8)
Each term in the second factor is multiplied by each term in the first factor, that is
x(x² - 7x + 8) - 5(x² - 7x + 8) ← distribute both parenthesis
= x³ - 7x² + 8x - 5x² + 35x - 40 ← collect like terms
= x³ - 12x² + 43x - 40