a三方-5a方b-24ab方 3ab平方-9a方B方+6A三方B平方
5X平方-5X-60 2X三方-13X平方-24X
a^3-5a^2b-24ab^2
=a(a^2-5ab-24b^2)
=a(a-8b)(a+3)
3ab^2-9a^2b^2+6a^3b^2
=3ab^2(1-3a+2a^2)
=3ab^2(1-2a)(1-a)