求下列分式的值:x-1/2x²-2,其中x=-2; ²-4xy+4y²/2x-4y,其中x=-1,y=-1/2.
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![求下列分式的值:x-1/2x²-2,其中x=-2; ²-4xy+4y²/2x-4y,其中x=-1,y=-1/2.](/uploads/image/z/1662907-67-7.jpg?t=%E6%B1%82%E4%B8%8B%E5%88%97%E5%88%86%E5%BC%8F%E7%9A%84%E5%80%BC%EF%BC%9Ax-1%2F2x%26%23178%3B-2%2C%E5%85%B6%E4%B8%ADx%3D-2%3B+%26%23178%3B-4xy%2B4y%26%23178%3B%2F2x-4y%2C%E5%85%B6%E4%B8%ADx%3D-1%2Cy%3D-1%2F2.)
求下列分式的值:x-1/2x²-2,其中x=-2; ²-4xy+4y²/2x-4y,其中x=-1,y=-1/2.
求下列分式的值:x-1/2x²-2,其中x=-2; ²-4xy+4y²/2x-4y,其中x=-1,y=-1/2.
求下列分式的值:x-1/2x²-2,其中x=-2; ²-4xy+4y²/2x-4y,其中x=-1,y=-1/2.
x-1/2x²-2
=(x-1)/2(x²-1)
=(x-1)/2(x+1)(x-1)
=1/2(x+1)
=1/2(-2+1)
=-1/2
x²-4xy+4y²/2x-4y
=(x-2y)²/2(x-2y)
=1/2(x-2y)
=1/2x-y
=1/2x(-1)+1/2
=-1/2+1/2
=0
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