先化简再求值:(a2/a-1)-a-1,其中a=2
a²/(a-1)-(a+1)
=(a²-a²+1)/(a-1)
=1/(a-1)
a=2代入
原式=1
a²/(a-1)-a-1
=a²/(a-1)-(a+1)
=[a²-(a+1)(a-1)]/(a-1)
=[a²-(a²-1)]/(a-1)
=1/(a-1)
【a=2】
=1/(2-1)
=1
表达好像不正确。
a²/(a-1)-a-1
=a²/(a-1)-(a+1)
=[a²-(a+1)(a-1)]/(a-1)
=[a²-(a²-1)]/(a-1)
=1/(a-1)
【a=2】
=1/(2-1)
=1
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