先化简,后求值:a2-2a+1分之a2-1+a-2分之2a-a2÷a,其中a=2分之3
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解决时间 2021-03-27 12:05
- 提问者网友：原来太熟悉了会陌生
- 2021-03-27 07:07
先化简,后求值:a2-2a+1分之a2-1+a-2分之2a-a2÷a,其中a=2分之3
最佳答案
- 五星知识达人网友：污到你湿
- 2021-03-27 08:02
解：
原式=[(a²-1)/(a²-2a+1)]+[(2a-a²)/(a-2)]÷a
=[(a+1)(a-1)/(a-1)²]+[-a(a-2)/(a-2)]×(1/a)
=[(a+1)/(a-1)]-1
=[(a+1)/(a-1)]-[(a-1)/(a-1)]
=[(a+1)-(a-1)]/(a-1)
=(a+1-a+1)/(a-1)
=2/(a-1)
当a=3/2时
原式=2/(3/2-1)
=2/(1/2)
=2×2
=4
原式=[(a²-1)/(a²-2a+1)]+[(2a-a²)/(a-2)]÷a
=[(a+1)(a-1)/(a-1)²]+[-a(a-2)/(a-2)]×(1/a)
=[(a+1)/(a-1)]-1
=[(a+1)/(a-1)]-[(a-1)/(a-1)]
=[(a+1)-(a-1)]/(a-1)
=(a+1-a+1)/(a-1)
=2/(a-1)
当a=3/2时
原式=2/(3/2-1)
=2/(1/2)
=2×2
=4
全部回答
- 1楼网友：归鹤鸣
- 2021-03-27 08:42
（a^2-1)/(a^2-2a+1)+(2a-a^2)/(a-2)÷a
=(a+1)/(a-1)-a÷a
=(a+1)/(a-1)-1
=2/(a-1),
a=3/2时原式=2/（3/2-1）=4.
=(a+1)/(a-1)-a÷a
=(a+1)/(a-1)-1
=2/(a-1),
a=3/2时原式=2/（3/2-1）=4.
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