试题:
先化简,再求值:
x-4
x-2
+
4
x2-4x+4
÷
x
x-2
,其中x=
2

答案:

我来补答
原式=
x-4
x-2
+
x-4
(x-2)^2
×
x-2
x

=
x-4
x-2
+
4
x(x-2)

=
x(x-4)
x(x-2)
+
4
x(x-2)

=
(x-2)2
x(x-2)

=
(x-2)
x

当x=
2
时,原式=
2
-2
2
=1-
2
 
 
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