Can someone please help I really don’t understand this please explain.

Answer:
The answer is option D.
Step-by-step explanation:
You have to multiply it :
h(x) × g(x) = (h×g)(x)
(h×g)(x) = (x² + 2x)(-3x + 4)
(h×g)(x) = -3x³ + 4x² - 6x² + 8x
(h×g)(x) = -3x³ - 2x² + 8x