急求(x+y)的三次方-y(x+y)的二次方+x的二次方(y+x)=( )(2x+y)
问题描述:
急求(x+y)的三次方-y(x+y)的二次方+x的二次方(y+x)=( )(2x+y)
答
(x+y)-y(x+y)+x(y+x) =(x+y)[(x+y)-y(x+y)+x] =(x+y)(x+2xy+y-xy-y+x) =(x+y)(2x+xy) =x(x+y)(2x+y) =(x+xy)(2x+y) (x+y)的三次方-y(x+y)的二次方+x的二次方(y+x)=(x+xy )(2x+y)