(4/x²-y²+x+y/xy²-x²y)÷(x+2y)(x-y)/x²y+2xy²,其中x=-1,y=-3...
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![(4/x²-y²+x+y/xy²-x²y)÷(x+2y)(x-y)/x²y+2xy²,其中x=-1,y=-3...](/uploads/image/z/5300076-12-6.jpg?t=%EF%BC%884%2Fx%26%23178%3B-y%26%23178%3B%2Bx%2By%2Fxy%26%23178%3B-x%26%23178%3By%EF%BC%89%C3%B7%EF%BC%88x%2B2y%EF%BC%89%EF%BC%88x-y%EF%BC%89%2Fx%26%23178%3By%2B2xy%26%23178%3B%2C%E5%85%B6%E4%B8%ADx%3D-1%2Cy%3D-3...)
(4/x²-y²+x+y/xy²-x²y)÷(x+2y)(x-y)/x²y+2xy²,其中x=-1,y=-3...
(4/x²-y²+x+y/xy²-x²y)÷(x+2y)(x-y)/x²y+2xy²,其中x=-1,y=-3.
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(4/x²-y²+x+y/xy²-x²y)÷(x+2y)(x-y)/x²y+2xy²,其中x=-1,y=-3...
原式=[4/(x+y)(x-y)-(x+y)/xy(x-y)]÷【(x+2y)(x-y)/xy(x+2y)]
=[4xy-(x+y)^2]/xy(x+y)(x-Y)*[xy/(x-y)]
=[-(x-y)^2]/xy(x+y)(x-y)*[xy/(x-y)]
=-1/(x+y)
当x=-1,y=-3时,原式=-1/(-1-3)=1/4
原式=[4/(x+y)(x-y)+(x+y)/xy(y-x)]÷[(x+2y)(x-y)/xy(x+2y)]
=[-4xy/xy(x+y)(y-x)+(x+y)(x+y)/xy(x+y)(y-x)]÷(x-y)/xy
=[(-4xy+x^2+2xy+y^2)/xy(x+y)(y-x)]*xy/(x-y)
=(x-y)^2/(x+y)(y-x)(x-y)
=-1/(x+y)
将x=-1,y=-3代入上式
原式=1/4