数学题(2x-y)²-4(x+y)(x-2y)
问题描述：
数学题(2x-y)²-4(x+y)(x-2y)
答
(2x-y)²-4(x+y)(x-2y)=4x²-4xy+y²-4(x²-xy-2y²）=9y²
数学题(2x-y)²-4(x+y)(x-2y)
(2x-y)²-4(x+y)(x-2y)=4x²-4xy+y²-4(x²-xy-2y²）=9y²