(6n-3m^2)(3m^2+6n)
问题描述：
(6n-3m^2)(3m^2+6n)
答
36n^2-9m^4
答
(6n-3m^2)(3m^2+6n)=36n^2-9m^4
答
(6n-3m^2)(3m^2+6n)=(6n-3m^2)(6n+3m^2)=(6n)^2-(3m^2)^2=36n^2-9m^4