x2-5x+2=0,
∴二次項(xiàng)系數(shù)a=1,一次項(xiàng)系數(shù)b=-5,常數(shù)項(xiàng)c=2,
∴△=b2-4ac=25-8=17>0,
∴x=
?b±
| ||
2a |
?(?5)±
| ||
2×1 |
5±
| ||
2 |
∴x1=
5+
| ||
2 |
5?
| ||
2 |
(2)由原方程,得
x2-5x+6-p2=0,
∴△=(-5)2-4×1×(6-p2)=1+4p2>0,
∴方程有兩個(gè)不相等的實(shí)數(shù)根.
?b±
| ||
2a |
?(?5)±
| ||
2×1 |
5±
| ||
2 |
5+
| ||
2 |
5?
| ||
2 |