作业帮已知:y=2x-5,求代数式[（x^2+y^2)-(x+y)^2-2y(x-y)]÷8y的值
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/06 10:34:29
![已知:y=2x-5,求代数式[（x^2+y^2)-(x+y)^2-2y(x-y)]÷8y的值](/uploads/image/z/12956188-4-8.jpg?t=%E5%B7%B2%E7%9F%A5%3Ay%3D2x-5%2C%E6%B1%82%E4%BB%A3%E6%95%B0%E5%BC%8F%5B%EF%BC%88x%5E2%2By%5E2%29-%28x%2By%29%5E2-2y%28x-y%29%5D%C3%B78y%E7%9A%84%E5%80%BC)
已知:y=2x-5,求代数式[（x^2+y^2)-(x+y)^2-2y(x-y)]÷8y的值
已知:y=2x-5,求代数式[（x^2+y^2)-(x+y)^2-2y(x-y)]÷8y的值
已知:y=2x-5,求代数式[（x^2+y^2)-(x+y)^2-2y(x-y)]÷8y的值
y=2x-5 y-2x=-5
[（x^2+y^2)-(x+y)^2-2y(x-y)]÷8y=[x^2+y^2-x^2-y^2-2xy-2y(x-y)]÷8y=[-2xy-2y(x-y)]÷8y
=y[-2x-2x+2y]÷8y=-(y-2x)/4 =5/4