(1)计算:22(212+418-348)(2)分解因式:(x2-2x)2+2(x2-2x)+1(3)先化简,再求值:x-1x÷(x-2x-1x),其中x=5+1.-数学

题目简介

(1)计算:22(212+418-348)(2)分解因式:(x2-2x)2+2(x2-2x)+1(3)先化简,再求值:x-1x÷(x-2x-1x),其中x=5+1.-数学

题目详情

(1)计算:
2
2
(2
12
+4
1
8
-3
48
)

(2)分解因式:(x2-2x)2+2(x2-2x)+1
(3)先化简,再求值:
x-1
x
÷(x-
2x-1
x
)
,其中x=
5
+1.
题型:解答题难度:中档来源:不详

答案

(1)原式=
2
2
×2
12
+
2
2
×4
class="stub"1
8
-
2
2
×3
48

=2
6
+2×class="stub"1
2
-class="stub"3
2
×4
6

=2
6
+1-6
6

=-1-4
6


(2)原式=(x2-2x+1)2
=[(x-1)2]2
=(x-1)4;

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

=class="stub"x-1
x
÷
x2-2x+1
x

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

=class="stub"1
x-1

当x=
5
+1时,原式=class="stub"1
5
+1-1
=
5
5

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