求文档:多项式乘多项式计算(3x-2y)(5x+3y)
问题描述:
求文档:多项式乘多项式计算(3x-2y)(5x+3y)
答
15X"-XY-6Y"
答
(a-b)(c+d)
=ac+ad-bc-bc
所以就=15x方+9xy-10xy-6y方
=15x方-xy-6y方
答
(3x-2y)(5x+3y)=3x(5x+3y)-2y(5x+3y)=3x×5x+3x×3y-2y×5x-2y×3y=15x^2+9xy-10xy-6y^2=15x^2-xy-6y^2多说一句:对于两个二项式相乘,其口诀是:前前、后后、里里、外外,即:前边乘以前边+后边乘以后边+里变乘以里边...