问题 解答题
先化简,再求值:
x2-4x+4
2x
÷
x2-2x
x2
+1,在0,1,2三个数中选一个合适的,代入求值.
答案

x2-4x+4
2x
÷
x2-2x
x2
+1

=

(x-2)2
2x
÷
x(x-2)
x2
+1

=

(x-2)2
2x
×
x2
x(x-2)
+1

=

x-2
2
+1

=

x
2

当x=0或2时,分式无意义,

故x只能等于1,

原式=

1
2

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