已知2x+y=4,求代数式[(x+y)²-(x-y)²-2y(x-1/2y)]÷4y的值（还没学因式分解）

来源：学生作业学帮网编辑：学帮网时间：2024/05/28 19:17:25

[(x+y)²-(x-y)²-2y(x-1/2y)]÷4y=[(x²+2xy+y²)-(x²-2xy+y²)-2xy+y²]÷4y=(2xy+y²)÷4y=y(2x+y)÷4y
=4/4=1

[(x+y)²-(x-y)²-2y(x-1/2y)]÷4y
=[(x²+2xy+y²)-(x²-2xy+y²)-2xy+y²]÷4y
=(2xy+y²)÷4y
=y(2x+y)÷4y
=4/4
=1

已知2x+y=4,求代数式[(x+y)²-(x-y)²-2y(x-1/2y)]÷4y的值 （还没学因式分解）