先化简,再求值:(1)(x²+2x)/(x²-x),其中x=10;(2)(3x²-xy)/9x²-6xy+y²,其中x=-8,y=2.
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![先化简,再求值:(1)(x²+2x)/(x²-x),其中x=10;(2)(3x²-xy)/9x²-6xy+y²,其中x=-8,y=2.](/uploads/image/z/5509242-18-2.jpg?t=%E5%85%88%E5%8C%96%E7%AE%80%2C%E5%86%8D%E6%B1%82%E5%80%BC%3A%281%29%28x%26%23178%3B%2B2x%29%2F%28x%26%23178%3B-x%29%2C%E5%85%B6%E4%B8%ADx%3D10%3B%282%29%283x%26%23178%3B-xy%29%2F9x%26%23178%3B-6xy%2By%26%23178%3B%2C%E5%85%B6%E4%B8%ADx%3D-8%2Cy%3D2.)
先化简,再求值:(1)(x²+2x)/(x²-x),其中x=10;(2)(3x²-xy)/9x²-6xy+y²,其中x=-8,y=2.
先化简,再求值:(1)(x²+2x)/(x²-x),其中x=10;
(2)(3x²-xy)/9x²-6xy+y²,其中x=-8,y=2.
先化简,再求值:(1)(x²+2x)/(x²-x),其中x=10;(2)(3x²-xy)/9x²-6xy+y²,其中x=-8,y=2.
(x²+2x)/(x²-x)
=x(x+2)/[x(x-1)]
=(x+2)/(x-1)
=(10+2)/(10-1)
=12/9
=4/3
(3x²-xy)/(9x²-6xy+y²)
=x(3x-y)/(3x-y)²
=x/(3x-y)
=-8/[3*(-8)-2]
=-8/[-24-2]
=-8/(-26)
=4/13