先化简 再求值:[4(xy-1)^2-(xy+2)(2-xy)]1/4xy,其中x=-2,y=1/5
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![先化简 再求值:[4(xy-1)^2-(xy+2)(2-xy)]1/4xy,其中x=-2,y=1/5](/uploads/image/z/1818806-14-6.jpg?t=%E5%85%88%E5%8C%96%E7%AE%80+%E5%86%8D%E6%B1%82%E5%80%BC%3A%5B4%28xy-1%29%5E2-%28xy%2B2%29%282-xy%29%5D1%2F4xy%2C%E5%85%B6%E4%B8%ADx%3D-2%2Cy%3D1%2F5)
先化简 再求值:[4(xy-1)^2-(xy+2)(2-xy)]1/4xy,其中x=-2,y=1/5
先化简 再求值:[4(xy-1)^2-(xy+2)(2-xy)]1/4xy,其中x=-2,y=1/5
先化简 再求值:[4(xy-1)^2-(xy+2)(2-xy)]1/4xy,其中x=-2,y=1/5
[4(xy-1)^2-(xy+2)(2-xy)]1/4xy
=[4(xy-1)^2 +(xy+2)(xy-2)]1/4xy
=[4(xy)²-8(xy)+4+(xy)²-4]÷(4xy)
=[5(xy)²-8(xy)]÷(4xy)
=(5xy-8)/4
已知x=-2,y=1/5,那么:xy=-2/5
所以:原式=(5xy-8)/4=[5*(-2/5)-8]/4=(-10)/4=-5/2