(1)计算:(a-b+b2a+b)•a+ba(2)先化简,再求值:(x-1x-x-2x+1)÷2x2-xx2+2x+1,其中x满足x2-x-1=0.-数学

题目简介

(1)计算:(a-b+b2a+b)•a+ba(2)先化简,再求值:(x-1x-x-2x+1)÷2x2-xx2+2x+1,其中x满足x2-x-1=0.-数学

题目详情

(1)计算:(a-b+
b2
a+b
)•
a+b
a

(2)先化简,再求值:(
x-1
x
-
x-2
x+1
)÷
2x2-x
x2+2x+1
,其中x满足x2-x-1=0.
题型:解答题难度:中档来源:不详

答案

(1)原式=
a2
a+b
class="stub"a+b
a

=a;
  
(2)原式=
x2-1-x2+2x
x(x+1)
÷
x(2x-1)
(x+1)2

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

=class="stub"x+1
x2

∵x2-x-1=0,
∴x2=x+1,
∴原式=class="stub"x+1
x+1
=1.

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