计算:(2x-y)2-4(x-y)(x+2y)
问题描述:
计算:(2x-y)2-4(x-y)(x+2y)
答
原式=4x2-4xy+y2-4(x2+xy-2y2)=4x2-4xy+y2-4x2-4xy+8y2=-8x+9y2.
计算:(2x-y)2-4(x-y)(x+2y)
原式=4x2-4xy+y2-4(x2+xy-2y2)=4x2-4xy+y2-4x2-4xy+8y2=-8x+9y2.