解得,x=
1 |
2 |
②當(dāng)k≠0時,∵方程有實數(shù)根,
∴b2-4ac≥0,
即:4+4k≥0,
解得,k≥-1,
又∵k≠0,
∴k≥-1且k≠0,
綜合上述可得,
k≥-1.
(2)當(dāng)k=2時,方程可化為2x2+2x=1
二次項系數(shù)化為1,得
x2+x=
1 |
2 |
配方得,
x2-
3 |
2 |
3 |
4 |
1 |
2 |
3 |
4 |
(x+
1 |
2 |
3 |
4 |
由此可得,
?x+
1 |
2 |
| ||
2 |
解得x1=
| ||
2 |
| ||
2 |
1 |
2 |
1 |
2 |
3 |
2 |
3 |
4 |
1 |
2 |
3 |
4 |
1 |
2 |
3 |
4 |
1 |
2 |
| ||
2 |
| ||
2 |
| ||
2 |