化简 (1) 2(4a的二次方b-3ab的二次方)+(-a的二次方-2ab的二次方)(2)(m的二次方-n的二次方)-3(2m的二次方-4n的二次方)(3)2m-3n+[6m-(3m-n)]

问题描述:

化简 (1) 2(4a的二次方b-3ab的二次方)+(-a的二次方-2ab的二次方)
(2)(m的二次方-n的二次方)-3(2m的二次方-4n的二次方)
(3)2m-3n+[6m-(3m-n)]

(1) 2*(4a^2b-3ab^2)+(-a^2-2ab^2)= 8a^2b-6ab^2-a^2-2ab^2= 8a^2b-a^2-8ab^2(2)(m^2-n^2)-3*(2m^2-4n^2)= m^2-n^2-6m^2+12n^2= -5m^2+11n^2(3)2m-3n+[6m-(3m-n)]= 2m-3n+6m-3m+n= 5m-2n