(m-2n-3)(3-m-2n)等于多少?算出来.写清楚点
问题描述：
(m-2n-3)(3-m-2n)等于多少?算出来.写清楚点
答
(m-2n-3)(3-m-2n)=[(-2n)+(m-3)][(-2n)-(m-3)]=(-2n)^2-(m-3)^2=4n^2-m^2+6m-9
(m-2n-3)(3-m-2n)等于多少?算出来.写清楚点
(m-2n-3)(3-m-2n)=[(-2n)+(m-3)][(-2n)-(m-3)]=(-2n)^2-(m-3)^2=4n^2-m^2+6m-9