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> 先化简,再求值:(1x-1+1x+1)•x-1x,其中x=-7.-数学
先化简,再求值:(1x-1+1x+1)•x-1x,其中x=-7.-数学
题目简介
先化简,再求值:(1x-1+1x+1)•x-1x,其中x=-7.-数学
题目详情
先化简,再求值:
(
1
x-1
+
1
x+1
)•
x-1
x
,其中x=-7.
题型:解答题
难度:中档
来源:不详
答案
原式=
class="stub"x+1+x-1
(x+1)(x-1)
•
class="stub"x-1
x
=
class="stub"2x
(x+1)(x-1)
•
class="stub"x-1
x
=
class="stub"2
x+1
,
当x=-7时,原式=
class="stub"2
-7+1
=-
class="stub"1
3
.
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题目简介
先化简,再求值:(1x-1+1x+1)•x-1x,其中x=-7.-数学
题目详情
答案
=
=
当x=-7时,原式=