先化简,再求值:其中x=2(x^2-2x-3/x^2-1-x+1/x-1)÷x-3/x-1
1个回答
展开全部
(x^2-2x-3/x^2-1-x+1/x-1)÷x-3/x-1
=[(x-3)(x+1)/(x-1)(x+1)-(x+1)/(x-1)]×(x-1)/(x-3)
=[(x-3)/(x-1)-(x+1)/(x-1)×(x-1)/(x-3)
=-4/(x-1)×(x-1)/(x-3)
=-4/(x-3)
当x=2时
原式=-4/(2-3)=4
=[(x-3)(x+1)/(x-1)(x+1)-(x+1)/(x-1)]×(x-1)/(x-3)
=[(x-3)/(x-1)-(x+1)/(x-1)×(x-1)/(x-3)
=-4/(x-1)×(x-1)/(x-3)
=-4/(x-3)
当x=2时
原式=-4/(2-3)=4
本回答由提问者推荐
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
