x/x^2+x+1=-1/2,求2x^2/(x^2-x+1)+x-1/x^3-1
答案:2 悬赏:0 手机版
解决时间 2021-04-10 02:10
- 提问者网友：我的未来我做主
- 2021-04-09 09:15
悬赏
最佳答案
- 五星知识达人网友：野慌
- 2021-04-09 09:25
x/(x^2+x+1)=-1/2
x^2+x+1=-2x
则x^2-x+1=-4x
且x^2+1=-3x
2x^2/(x^2-x+1)+(x-1)/(x^3-1)
=2x^2/(x^2-x+1)+(x-1)/(x-1)(x^2+x+1)
=2x^2/(x^2-x+1)+1/(x^2+x+1)
=2x^2/(-4x)+1/(-2x)
=-x/2-1/2x
=-(x^2+1)/2x
=-(-3x)/2x
=3/2
x^2+x+1=-2x
则x^2-x+1=-4x
且x^2+1=-3x
2x^2/(x^2-x+1)+(x-1)/(x^3-1)
=2x^2/(x^2-x+1)+(x-1)/(x-1)(x^2+x+1)
=2x^2/(x^2-x+1)+1/(x^2+x+1)
=2x^2/(-4x)+1/(-2x)
=-x/2-1/2x
=-(x^2+1)/2x
=-(-3x)/2x
=3/2
全部回答
- 1楼网友：一把行者刀
- 2021-04-09 10:52
2x ÷( 2x - 5 ) - 2 ÷ ( 2x + 5) =1
两边同乘以(2x-5)(2x+5):
2x(2x+5)-2(2x-5)=(2x+5)(2x-5)
4x^2+10x-4x+10=4x^2-25
6x=-35
x=-35/6
我要举报
如以上回答内容为低俗、色情、不良、暴力、侵权、涉及违法等信息，可以点下面链接进行举报！
点此我要举报以上问答信息
大家都在看
推荐资讯