(1)(2)(3)(4)先化简,再求值:,其中a=一1,b=.

发布时间:2020-08-06 11:05:17

(1)
(2)
(3)
(4)先化简,再求值:,其中a=一1,b=.

网友回答

解:1)
=
=
=;

(2)
=

=1-
=
=-;

(3)
=(-)×
=-
=
=;

(4)
=
=
=2-=,
把a=一1,b=代入上式得:原式==1.
解析分析:(1)先把要求的式子进行通分,再合并,即可求出
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