作业帮先化简,再求值：[(x+2y)²-（x+y）（3x-y）-5y²]÷2x,其中x=-2,y=1/2
来源：学生作业帮助网 编辑：作业帮 时间：2024/04/29 13:28:28
![先化简,再求值：[(x+2y)²-（x+y）（3x-y）-5y²]÷2x,其中x=-2,y=1/2](/uploads/image/z/264125-29-5.jpg?t=%E5%85%88%E5%8C%96%E7%AE%80%2C%E5%86%8D%E6%B1%82%E5%80%BC%EF%BC%9A%5B%28x%2B2y%29%26%23178%3B-%EF%BC%88x%2By%EF%BC%89%EF%BC%883x-y%EF%BC%89-5y%26%23178%3B%5D%C3%B72x%2C%E5%85%B6%E4%B8%ADx%3D-2%2Cy%3D1%2F2)
先化简,再求值：[(x+2y)²-（x+y）（3x-y）-5y²]÷2x,其中x=-2,y=1/2
先化简,再求值：[(x+2y)²-（x+y）（3x-y）-5y²]÷2x,其中x=-2,y=1/2
先化简,再求值：[(x+2y)²-（x+y）（3x-y）-5y²]÷2x,其中x=-2,y=1/2
[(x+2y)²-（x+y）（3x-y）-5y²]÷2x,其中x=-2,y=1/2
=(x²+4xy+4y²-3x²-2xy+y²-5y²)÷2x
=(-2x²+2xy)÷2x
=-x+y
=2+1/2
=2.5
(x²+4xy+4y²-3x²+xy-3xy+y²-5y²)/2x
=（-2x²+2xy)/2x
=-x+y
=2+1/2
=2.5
[(x+2y)²-（x+y）（3x-y）-5y²]÷2x
=-2x[x-y]÷2x
=-x+y
=-（-2）+1/2
=5/2
......