Step-by-step explanation:
(-2a² + s)(5a² - 6s)
= (-2a²)(5a²) + (-2a²)(-6s) + (s)(5a²) + (s)(-6s)
= -10a⁴ + 12a²s + 5a²s - 6s²
= -10a⁴ + 17a²s - 6s². (1st option)
