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> 先化简,再求值:x2-1x+2÷(1x+2-1),其中x=13.-数学
先化简,再求值:x2-1x+2÷(1x+2-1),其中x=13.-数学
题目简介
先化简,再求值:x2-1x+2÷(1x+2-1),其中x=13.-数学
题目详情
先化简,再求值:
x
2
-1
x+2
÷(
1
x+2
-1)
,其中x=
1
3
.
题型:解答题
难度:中档
来源:高要市一模
答案
x
2
-1
x+2
÷(
class="stub"1
x+2
-1)
=
(x+1)(x-1)
x+2
÷(
class="stub"1
x+2
-
class="stub"x+2
x+2
)
=
(x+1)(x-1)
x+2
÷
class="stub"1-x-2
x+2
=
(x+1)(x-1)
x+2
•(-
class="stub"x+2
x+1
)
=-(x-1)
=-x+1,
当x=
class="stub"1
3
时,原式=-
class="stub"1
3
+1=
class="stub"2
3
.
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题目简介
先化简,再求值:x2-1x+2÷(1x+2-1),其中x=13.-数学
题目详情
答案
=
=
=
=-(x-1)
=-x+1,
当x=