若1/x-1/y=2 xy/x方-y方的值为几?

冷雪儿2022-10-04 11:39:541条回答

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虚幻的废墟共回答了22个问题 | 采纳率95.5%: 由1/x-1/y=2得(y-x)/xy=2 y-x=2xy
xy/(x²-y²)==xy/[(x+y)(x-y)]=-xy/[(x+y)(y-x)]=-xy/[2xy(x+y)]=-1/[2(x+y)]; 1年前

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