①x/(x2-1) ·(x2+x)/x2其中x=2 ②(x2-1)/(x2+4x+4)÷(x+1).(x+2﹚/﹙1-x﹚其中x=-3
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解决时间 2021-02-15 06:46
- 提问者网友：心如荒岛囚我终老
- 2021-02-15 03:52
①x/(x2-1) ·(x2+x)/x2其中x=2 ②(x2-1)/(x2+4x+4)÷(x+1).(x+2﹚/﹙1-x﹚其中x=-3
最佳答案
- 五星知识达人网友：慢性怪人
- 2021-02-15 05:14
①x/(x^2-1) ·(x^2+x)/x^2
=x^2(x+1)/[(x+1)(x-1)x^2]
=1/(x-1)
=1
②(x^2-1)/(x^2+4x+4)÷(x+1).(x+2﹚/﹙1-x﹚
=-(x-1)(x+1)(x-1)/[(x+2)^2(x+1).(x+2﹚]
=-(x-1)²/(x+2)³
=-16/(-1)
=16
=x^2(x+1)/[(x+1)(x-1)x^2]
=1/(x-1)
=1
②(x^2-1)/(x^2+4x+4)÷(x+1).(x+2﹚/﹙1-x﹚
=-(x-1)(x+1)(x-1)/[(x+2)^2(x+1).(x+2﹚]
=-(x-1)²/(x+2)³
=-16/(-1)
=16
全部回答
- 1楼网友：独行浪子会拥风
- 2021-02-15 07:02
(x—1)(x2)=2(x2)
解：移项得：(x—1)(x2)-2(x2) =0
提取公因式得：x2(x-1-2)=0
x2=0 x-3=0
x1=0 x2=3
- 2楼网友：鱼芗
- 2021-02-15 06:09
①
x/(x²-1)×(x²+x)/x²
=x²(x+1)/x²(x+1)(x-1)
=1/(x-1)
=1/(2-1)
=1
②
(x²-1)/(x²+4x+4)÷(x+1)(x+2)/(1-x)
=(x+1)(x-1)(1-x)/(x+2)²(x+1)
=-(x-1)²/(x+2)²
=-[(x-1)/(x+2)]²
=-[(-3-1)/(-3+2)]²
=-4²
=16
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