先化简再求值:(x²+2x-8/x³+2x²+x)÷(x-2/x)其中x=-4/5
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![先化简再求值:(x²+2x-8/x³+2x²+x)÷(x-2/x)其中x=-4/5](/uploads/image/z/758194-34-4.jpg?t=%E5%85%88%E5%8C%96%E7%AE%80%E5%86%8D%E6%B1%82%E5%80%BC%EF%BC%9A%EF%BC%88x%26%23178%3B%2B2x-8%2Fx%26%23179%3B%2B2x%26%23178%3B%2Bx%EF%BC%89%C3%B7%EF%BC%88x-2%2Fx%EF%BC%89%E5%85%B6%E4%B8%ADx%3D-4%2F5)
先化简再求值:(x²+2x-8/x³+2x²+x)÷(x-2/x)其中x=-4/5
先化简再求值:(x²+2x-8/x³+2x²+x)÷(x-2/x)
其中x=-4/5
先化简再求值:(x²+2x-8/x³+2x²+x)÷(x-2/x)其中x=-4/5
原式
=(x+4)(x-2)/x(x+1)² ÷ (x-2)(x+5)/x(x+1)
=1/(x+1)
=1/(-4/5+1)
=5
(x²+2x-8)/(x³+2x²+x)÷[(x-2)/x*(x+4)/(x+1)]
=(x+4)(x-2)/[x(x²+2x+1)]÷{(x-2)(x+4)/[x(x+1)]}
=(x+4)(x-2)/[x(x+1)²]*x(x+1)/[(x-2)(x+4)]
=1/(x+1)
=1/(-4/5+1)
=1/(1/5)
=5