问题 解答题
计算:
(1)(-
1
x
1
x2+x
       
(2)
a
a-1
÷
a2-a
a2-1
-
1
a-1
答案

(1)原式=-

1
x
•x(x+1)

=-(x+1)

=-x-1;

(2)原式=

a
a-1
(a+1)(a-1)
a(a-1)
-
1
a-1

=

a+1
a-1
-
1
a-1

=

a
a-1

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