先化简,再求值:(2x2-2x-1x2-4x+4)÷x-4x,其中x=12.-数学

题目简介

先化简,再求值:(2x2-2x-1x2-4x+4)÷x-4x,其中x=12.-数学

题目详情

先化简,再求值:(
2
x2-2x
-
1
x2-4x+4
x-4
x
,其中x=
1
2
题型:解答题难度:中档来源:不详

答案

(class="stub"2
x2-2x
-class="stub"1
x2-4x+4
)÷class="stub"x-4
x

=(class="stub"2
x( x-2)
-class="stub"1
(x-2)2
)÷class="stub"x-4
x

=(
2(x-2)
x(x-2)2
-class="stub"x
x(x-2)2
)•class="stub"x
x-4

=class="stub"x-4
x(x-2)2
•class="stub"x
x-4

=class="stub"1
(x-2)2

当x=class="stub"1
2
时,原式=class="stub"1
(x-2)2
=class="stub"4
9

更多内容推荐