已知x-3y=0,求(2x+y)/(x^2-2xy+y^2)*(x-y)的值已知x-3y=0,求(2x+y)/(x^2-2xy+y^2)*(x-y)的值

来源:学生作业帮助网 编辑:作业帮 时间:2022/09/25 01:13:23

已知x-3y=0,求(2x+y)/(x^2-2xy+y^2)*(x-y)的值
已知x-3y=0,求(2x+y)/(x^2-2xy+y^2)*(x-y)的值

2x+y/x^2-2xy+y^2)*(x-y)=2x+y/(x-y)^2*(x-y)=2x+y/x-yx-3y=0.x=3y将x=3y带入2x+y/x-y=6y+y/3y-y=7/2(二分之七)

x=3y
(2x+y)/(x^2-2xy+y^2)*(x-y)
=(2x+y)(x-y)/(x-y)^2
=(2x+y)/(2x-y)
=[2*3y+y)]/[2*3y-y]
=7y/5y
=7/5

x=3y
(2x+y)/(x-y)^3
=7y/8y^2
=7/8y

分母有中括号吗,@#¥%&