先化简,再求值:[(x-3)/(x^2-2x-3)-x/(x^2-1)]÷1/(x+1),其中x=-1/2
2个回答
展开全部
[(x-3)/(x^2-2x-3)-x/(x^2-1)]÷1/(x+1)
=[(x-3)/(x-3)(x+1)-x/(x+1)(x-1)]÷1/(x+1)
=(x-1-x)/(x+1)(x-1)÷1/x+1
=-1/(x+1)(x-1)÷1/x+1
=-(x+1)/(x+1)(x-1)
=-1/(x-1)
当x=-1/2时
-1/(x-1)
=-1/(-1/2)-1
=-1/(-3/2)
=1÷3/2
=1×2/3
=2/3
累死了,自己打的!!!满意回答做错了,真不知道他/她是从哪摘的!!
=[(x-3)/(x-3)(x+1)-x/(x+1)(x-1)]÷1/(x+1)
=(x-1-x)/(x+1)(x-1)÷1/x+1
=-1/(x+1)(x-1)÷1/x+1
=-(x+1)/(x+1)(x-1)
=-1/(x-1)
当x=-1/2时
-1/(x-1)
=-1/(-1/2)-1
=-1/(-3/2)
=1÷3/2
=1×2/3
=2/3
累死了,自己打的!!!满意回答做错了,真不知道他/她是从哪摘的!!
已赞过
已踩过<
评论
收起
你对这个回答的评价是?
推荐律师服务:
若未解决您的问题,请您详细描述您的问题,通过百度律临进行免费专业咨询