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> 先化简,再求值:(11-x-1)(1x2-1),其中x=2-1.-数学
先化简,再求值:(11-x-1)(1x2-1),其中x=2-1.-数学
题目简介
先化简,再求值:(11-x-1)(1x2-1),其中x=2-1.-数学
题目详情
先化简,再求值:
(
1
1-x
-1)(
1
x
2
-1)
,其中x=
2
-1.
题型:解答题
难度:中档
来源:宁夏
答案
原式=
class="stub"1-1+x
1-x
•
1-
x
2
x
2
=
class="stub"x
1-x
•
(1-x)(1+x)
x
2
=
class="stub"x+1
x
;
当x=
2
-1时,原式=
2
-1+1
2
-1
=2+
2
.
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题目简介
先化简,再求值:(11-x-1)(1x2-1),其中x=2-1.-数学
题目详情
答案
=
=
当x=