x/y=3,求x²+y²-xy/x²-y²的值.

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x/y=3,求x²+y²-xy/x²-y²的值.x/y=3,求x²+y²-xy/x²-y²的值.x/y=3,求x

x/y=3,求x²+y²-xy/x²-y²的值.
x/y=3,求x²+y²-xy/x²-y²的值.

x/y=3,求x²+y²-xy/x²-y²的值.
∵x/y=3
∴x=3y
∴(x²+y²-xy)/(x²-y²)=(9y²+y²-3y²)/(9y²-y²)=7y²/8y²=7/8