[x-1-8/(X-1)]÷(x+3)/(x+1)
=[(x-1)^2-8]/(x-1)*(x+1)/(x+3)
=[(x-1)^2-8]*(x+1)/[(x-1)(x+3)]
=[(x-1+2√2)(x-1-2√2](x+1)/[(x-1)(x+3)]
=[(3-√2-1+2√2)(3-√2-1-2√2](3-√2+1)/[(3-√2-1)(3-√2+3)]
=(2+√2)(2-3√2)(4-√2)/[(2-√2)(6-√2)]
=-14√2/[14-8√2]
=-(56+49√2)/17 .
先化简,再求值:[X-1-8/(X-1)]÷(x+3)/(x+1) 其中x=3-根号2
先化简,再求值:[X-1-8/(X-1)]÷(x+3)/(x+1) 其中x=3-根号2
x-1和8不是一个整体啦
x-1和8不是一个整体啦
数学人气:323 ℃时间:2019-09-20 06:13:20
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