Answer:
x³ + 5x² + 2x - 8
Step-by-step explanation:
1) Distribute
(x + 4) (x² + x - 2)
x(x² + x - 2) + 4 ( x² + x - 2)
2) Distribute
x(x² + x - 2) + 4 (x² + x - 2)
x³ + x² - 2x + 4 (x² + x - 2)
3) Distribute
x³ + x² - 2x + 4 (x² + x - 2)
x³ + x² - 2x + 4x² + 4x - 8
4) Combine like terms
x³ + x² - 2x + 4x² + 4x - 8
x³ + 5x² - 2x + 4x - 8
5) Combine like terms
x³ + 5x² - 2x + 4x - 8
x³ + 5x² + 2x - 8
