Answer:
(4x + 5)(x² + 25)
Step-by-step explanation:
Given
4x³ + 5x² + 100x + 125 ( factor the first/second and third/fourth terms )
= x²(4x + 5) + 25(4x + 5) ← factor out (4x + 5) from each term
= (4x + 5)(x² + 25)