计算：(2x-y)²-4(x-y)(x+2y)

计算：(2x-y)²-4(x-y)(x+2y)
计算：(2x-y)²-4(x-y)(x+2y)

计算：(2x-y)²-4(x-y)(x+2y)
(2x-y)²-4(x-y)(x+2y)
=4x²-4xy+y²-4(x²+xy-2y²)
=4x²-4xy+y²-4x²-4xy+8y²
=9y²-8xy
=y(9y-8x)

9y2-8xy 采纳谢谢

(2x-y)²-4(x-y)(x+2y)
=4x²-4xy+y² -4(x²+ 2xy-xy+2y²)
= 4x²-4xy+y² - 4(x² + xy+2y²)
= 4x²-4xy+y²-4x²-4xy-8y²
= -8xy-7y²
=-y(8x+7y)