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题目
题型:解答题难度:一般来源:不详
化简:
(1)
2a
a2-4
+
1
2-a

(2)
x2
x-1
+
1
1-x

(3)
a2-2a+1
a-1
-(a-2)

(4)
m
m-n
-
n
m+n
+
2mn
m2-n2
答案
(1)原式=
2a
(a+2)(a-2)
-
a+2
(a+2)(a-2)

=
2a-a-2
(a+2)(a-2)

=
a-2
(a+2)(a-2)

=
1
a+2


(2)原式=
x2
x-1
-
1
x-1

=
(x+1)(x-1)
x-1

=x+1;

(3)原式=(a-1)-(a-2)
=a-1-a+2
=1;

(4)原式=
m(m+n)-n(m-n)+2mn
(m+n)(m-n)

=
(m-n)2
(m+n)(m-n)

=
m-n
m+n
核心考点
试题【化简:(1)2aa2-4+12-a(2)x2x-1+11-x(3)a2-2a+1a-1-(a-2)(4)mm-n-nm+n+2mnm2-n2.】;主要考察你对分式的加减运算等知识点的理解。[详细]
举一反三
下列运算中,错误的是(  )
A.
a
a2-b2
-
b
b2-a2
=
1
a-b
B.
8
x2-4
+
3
2-x
=-
3x-2
x2-4
C.
n
m+n
+
nm
n2+m2
=
n2
m2-n2
D.
2y
y2-9
-
1
y+3
=
1
y-3
题型:单选题难度:一般| 查看答案
2xy-y2
x2-y2
+
x-y
x+y
=
m
x2-y2
,则m=______.
题型:填空题难度:一般| 查看答案
观察下列各式:
1
1×3
=
1
2
(1-
1
3
)
1
3×5
=
1
2
(
1
3
-
1
5
)
1
5×7
=
1
2
(
1
5
-
1
7
)
,…,根据观察计算:
1
1×3
+
1
3×5
+
1
5×7
+…+
1
(2n-1)×(2n+1)
=______(n为正整数).
题型:填空题难度:一般| 查看答案
a+2
a-2
-
a-2
a+2
-
8a
a2-4
=______.
题型:填空题难度:一般| 查看答案
计算:
(1)
m+2n
n-m
+
n
n-m
-
2m
m-n

(2)
x2
x-1
-x-1
题型:解答题难度:一般| 查看答案
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