I ONLY HAVE 3 MINUTES PLEASE HELP

Answer:
a × (3a² - 15ab + 5b²)
Step-by-step explanation:
3a³ - 15a²b + 5ab²
((3 × (a³)) - ((15 × (a²)) × b)) + 5ab²
((3 × (a³)) - ((3 × 5a²) × b)) + 5ab²
(3a³ - (3 × 5a²b)) + 5ab²
3a³ - 15a²b + 5ab²
a × (3a² - 15ab + 5b²)
3a² - 15ab + 5b²
a × (3a² - 15ab + 5b²)