求(3x^2+9x+7)/(x+1)-(2x^2+5x-3)/(x-1)-(x^3+x-1)/(x^2-1)的值

zmj52592022-10-04 11:39:541条回答

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的排练之中共回答了22个问题 | 采纳率86.4%: (3x^2+9x+7)/(x+1)-(2x^2+5x-3)/(x-1)-(x^3+x-1)/(x^2-1)
=[(3x²+9x+7)(x-1)-(2x²+5x-3)(x+1)-(x³+x-1)]/(x²-1)
=[3x³-3x²+9x²-9x+7x-7-(2x³+2x²+5x²+5x-3x-3)-(x³+x-1)]/(x²-1)
=(3x³+6x²-2x-7-2x³-7x²-2x+3-x³-x+1)/(x²-1)
=(-x²-5x-3)/(x²-1)
=-(x²+5x+3)/(x²-1)
如果本题有什么不明白可以追问,; 1年前

(3x^2+9x+7)/(x+1)-(2x^2+4x-3)/(x-1)-(x^3+x+1)/(x^2-1)= (3x^2+9x+7)/(x+1)-(2x^2+4x-3)/(x-1)-(x^3+x+1)/(x^2-1)= SORRY打错了 (3x^2+9x+7)/(x-1)-(2x^2+4x-3)/(x+1)-(x^3+x+1)/(x^2-1)= 莫小西1年前4: 网尘之叩共回答了20个问题 | 采纳率85%

=（3x^2+9x+7)（x+1）/（x^2-1）-（2x^2+4x-3）(x-1)/（x^2-1）-（x^3+x+1)/(x^2-1)
=（3x^3+12x^2+16x+7）/（x^2-1）-（2x^3+2x^2-7x+3）/（x^2-1）-（x^3+x+1)/(x^2-1）
=（10x^2+22x+3）/(x^2-1）

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(3x^2+9x+7)/(x+1)-(2x^2-4x+3)/(x-1)-(x^3+x+1)/(x^2-1) (3x^2+9x+7)/(x+1)-(2x^2-4x+3)/(x-1)-(x^3+x+1)/(x^2-1) 不许通分,有更好的办法 只是第一步不许通分啊 shanjiao01年前1: hxp68 共回答了20个问题 | 采纳率95%

(3x^2+9x+7)/(x+1)-(2x^2-4x+3)/(x-1)-(x^3+x+1)/(x^2-1)
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=(8x^2-8+x-1-x-1-2x-1)/(x^2-1)
=(8x^2-2x-11)/(x^2-1)

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(3x^2+9x+7)/(x+1)-(2x^2+4x-3)/(x-1)-(x^3+x+1)/(x^2-1)= 我就是那个人11年前1: 传说的灵魂共回答了12个问题 | 采纳率91.7%

=[(3x^2+9x+7)(x-1)-(2x^2+4x-3)(x+1)-(x^3+x+1)]/(x^2-1)=(4x+5)/(1-x^2)

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已知x^2-3x+1=0求(1)-3x^2+9x+7 ;(2)x^2+1/x^2 ;(3)2x^3-3x^2-7x+1 zjf7810281年前2: 佳和共回答了17个问题 | 采纳率88.2%

已知x²-3x+1=0,求(1)-3x²+9x+7 ;(2)x²+(1/x²);(3)2x³-3x²-7x+1(1).∵x²-3x+1=0,∴x²-3x=-1；故-3x²+9x+7=-3(x²-3x)+7=3+7=10;(2).∵x²-3x+1=0,∴x-3+(1/x)=...

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计算:再问一题：(3x^2+9x+7)/(x+1)-(2x^2-4x+3)/(x-1)-(x^3+x+1)/(x^2-1 计算: 再问一题： (3x^2+9x+7)/(x+1)-(2x^2-4x+3)/(x-1)-(x^3+x+1)/(x^2-1)=? 虽然看着有点烦 天使在唱歌LALA1年前1: yubuloveshui 共回答了25个问题 | 采纳率96%

我用word编辑的,截图给你,要是看不清在和我要原文件,这道题的可能推广我也写了,希望你学习的时候能够举一反三,当让也希望我能帮助你

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解方程(3x^2+9x+7)/(x+1)-(2x^2+4x-3)/(x-1)-(x^3+x+1)/(x^2-1)=0 解方程(3x^2+9x+7)/(x+1)-(2x^2+4x-3)/(x-1)-(x^3+x+1)/(x^2-1)=0 别从网上随便搜一个,要求自己答. 如果打字麻烦,可以发图或者用简便的办法, eligang1年前1: 7799650 共回答了26个问题 | 采纳率92.3%

方程两边同时乘以x²-1:
(3x²+9x+7)(x-1)-(2x²+4x-3)(x+1)-(x³+x+1)=0
3x^3+9x^2+7x-3x^2-9x-7-(2x^3+4x^2-3X+2x^2+4x-3)-x^3-x-1=0
3x^3+6x^2-2x-7-2x^3-4x^2+3x-2x^2-4x+3-x^3-x-1=0
0*x^3+0*x^2-4x-7-1+3=0
-4x-5=0
-4x=5x
x=-5/4
经检验x=-5/4为原方程的解.
望采纳!谢谢!

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(3x^2+9x+7)/(x+1)-(2x^2+4x-3)/(x-1)-(x^3+x+1)/(x^2-1)这个题. (3x^2+9x+7)/(x+1)-(2x^2+4x-3)/(x-1)-(x^3+x+1)/(x^2-1)这个题. 难道到了[(3x^2+9x+7)(x-1)-(2x^2+4x-3)(x+1)-(x^3+x+1)]/(x^2-1)这一步就直接出了答案-(4x+5)/(x^2-1)了吗? 笨小虾1年前1: bodazhang 共回答了17个问题 | 采纳率82.4%

(3x²+9x+7)/(x+1)-(2x²+4x-3)/(x-1)-(x^3+x+1)/(x²-1)
=(3x²+9x+7)/(x+1)-(2x²+4x-3)/(x-1)-(x^3+x+1)/[(x+1)(x-1)]
=[(3x²+9x+7)(x-1)-(2x²+4x-3)(x+1)-(x^3+x+1)]/[(x+1)(x-1)]
=[3x^3+9x²+7x-3x²-9x-7-2x^3-4x²+3x-2x²-4x+3-x^3-x-1]/[(x+1)(x-1)]
=(5x-5)/[(x+1)(x-1)]
=5/(x+1)

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