问题 解答题
计算:(
x+2
x
-
x-1
x-2
x-4
x
答案

(

x+2
x
-
x-1
x-2
x-4
x

=

(x+2)(x-2)-x(x-1)
x(x-2)
×
x
x-4

=

1
x-2

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