已知x^2-6xy+9y^2=0,求(x-y)/(x+y)

已知x^2-6xy+9y^2=0,求(x-y)/(x+y)
已知x^2-6xy+9y^2=0,求(x-y)/(x+y)

已知x^2-6xy+9y^2=0,求(x-y)/(x+y)
x²-6xy+9y²=0
（x-3y)²=0
x-3y=0
x=3y
(x-y)/(x+y)
=(3y-y)/(3y+y)
=2y/4y
=1/2

x^2-6xy+9y^2=0
(x-3y)^2=0
x=3y
(x-y)/(x+y)=(3y-y)/(3y+y)=1/2

1/2

1/2
x^2-6xy+9y^2=0 即（x-3y)^2=0, 所以x=3y
(x-y)/(x+y)=(3y-y)/(3y+y)=1/2