若1991＜x
问题描述：
若1991＜x
数学人气：946 ℃时间：2020-05-11 18:27:44
优质解答
若1991＜x(|x-1|-|x-1991|)*(|x-1990|+|x-2000|)
=[x-1-(x-1991)]*[x-1990+2000-x]
=[x-1-x+1991][10]
=1990*10
=19900
=[x-1-(x-1991)]*[x-1990+2000-x]
=[x-1-x+1991][10]
=1990*10
=19900
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答
若1991＜x(|x-1|-|x-1991|)*(|x-1990|+|x-2000|)
=[x-1-(x-1991)]*[x-1990+2000-x]
=[x-1-x+1991][10]
=1990*10
=19900