已知x:y=3,则分式x^2-y^2分之(x-y)^2=?

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已知x:y=3,则分式x^2-y^2分之(x-y)^2=?
已知x:y=3,则分式x^2-y^2分之(x-y)^2=?

已知x:y=3,则分式x^2-y^2分之(x-y)^2=?
要求的分式=(x-y)²/x²-y²
=(x-y)(x-y)/(x+y)(x-y)
=x-y/x+y
根据x:y=3 可知x=3y
所以原式=x-y/x+y=3y-y/3y+y=2y/4y=1/2

(x-y)^2/(x^2-y^2)=(x-y)(x-y)/(x+y)(x-y)=(x-y)/(x+y)
又因为x:y=3,所以x=3y,,代入得,(x-y)/(x+y)=1/2

1/2

不会在电脑上写字 写的很难看 请见谅