摘要:若设 0.2=0.2222--①.则-② 则 ②-①,得
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已知方程2x2+3=5
-3x.若设
=y,则原方程可化为( )
| 2x2+3x+9 |
| 2x2+3x+9 |
| A、y2+5y+6=0 |
| B、y2-5y-6=0 |
| C、y2-5y+6=0 |
| D、y2+5y-6=0 |
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| 2x2+3x+9 |
| 2x2+3x+9 |
| A、y2+5y+6=0 |
| B、y2-5y-6=0 |
| C、y2-5y+6=0 |
| D、y2+5y-6=0 |