题目内容
已知x1,x2分别是一元二次方程2x2-6x-3=0的两个实数根,则代数式
+
的值为______.
| 1 |
| x1 |
| 1 |
| x2 |
| 1 |
| x1 |
| 1 |
| x2 |
| x1+x2 |
| x1•x2 |
x1•x2=
| -3 |
| 2 |
| 3 |
| 2 |
x1+x2=-
| -6 |
| 2 |
把②③代入①,解得
| 1 |
| x1 |
| 1 |
| x2 |
∴答案是-2.
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题目内容
| 1 |
| x1 |
| 1 |
| x2 |
| 1 |
| x1 |
| 1 |
| x2 |
| x1+x2 |
| x1•x2 |
| -3 |
| 2 |
| 3 |
| 2 |
| -6 |
| 2 |
| 1 |
| x1 |
| 1 |
| x2 |