已知x-3y=0,求(x²-2xy+y²/x-y)-2y的值
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已知x-3y=0,求(x²-2xy+y²/x-y)-2y的值
已知x-3y=0,求(x²-2xy+y²/x-y)-2y的值
已知x-3y=0,求(x²-2xy+y²/x-y)-2y的值
(x²-2xy+y²)/(x-y)-2y
=[(x-y)²/(x-y)]-2y
=(x-y)-2y
=x-3y
=0
(x²-2xy+y²/x-y)-2y
=(x-y)²/(x-y)-2y
=x-y-2y
=x-3y
=0
(x²-2xy+y²/x-y)-2y 通分,得
(x²-2xy+y²-2xy+2y²)/(x-y)
=(x²-4xy+3y²)/(x-y)
=(x-y)(x-3y)/(x-y)
=x-3y
由题知 x-3y=0