摘要:21.用换元法解方程 .
网址:http://m.1010jiajiao.com/timu3_id_438642[举报]
用换元法解方程x2+x+
=8,若设x2+x=y,则原方程化为关于y的整式方程是( )
| 7 |
| x2+x |
| A、y2-8y+7=0 |
| B、y2-8y-7=0 |
| C、y2+8y+7=0 |
| D、y2+8y-7=0 |
网址:http://m.1010jiajiao.com/timu3_id_438642[举报]
| 7 |
| x2+x |
| A、y2-8y+7=0 |
| B、y2-8y-7=0 |
| C、y2+8y+7=0 |
| D、y2+8y-7=0 |