(-3a3)2.a3+(-4a)2.a^7-(5a3)3
=9a^6*a^3+16a^2*a^7-125a^9
=9a^9+12a^9-125a^9
=100a^9
如果帮到你,请记得采纳,O(∩_∩)O谢谢