(2x-y)的平方-4(x+y)(x+2y) 速度、要过程,

问题描述:

(2x-y)的平方-4(x+y)(x+2y) 速度、要过程,

=4x方-4xy+y方-4(x方+2xy+xy+2y方)
=4x方-4xy+y方-4x方-12xy-8y方
=-16xy-7y方