问题 选择题
下列计算正确的是(  )
A.
1
(m-1)3
+
1
(1-m)3
=0
B.
x
(x-1)4
+
1
(1-x)4
=
1
(x-1)3
C.
x-1
1-x
-
1-x
x-1
=2
D.
1
(x+1)(x-2)
-
1
x2-x-2
=
2
(x+1)(x-2)
答案

A、

1
(m-1)3
+
1
(1-m)3
=0,故A正确;

B、原式=

x+1
1-x4
,故B错误;

C、

x-1
1-x
-
1-x
x-1
=0,故C错误;

D、

1
(x+1)(x-2)
-
1
x2-x-2
=0,故D错误;

故选A.

单项选择题
问答题 简答题