题目内容
(1)计算:
-
-|
-2|
(2)解方程:2x2-5x+1=0.
| (-2)2 |
| 1 | ||||
|
| 3 |
(2)解方程:2x2-5x+1=0.
(1)原式=|-2|-(
+
)-(2-
)=2-
-
-2+
=-
;
(2)∵a=2,b=-5,c=1,
△=b2-4ac=(-5)2-4×2×1=17>0,
∴x=
,
则x1=
,x2=
.
| 3 |
| 2 |
| 3 |
| 3 |
| 2 |
| 3 |
| 2 |
(2)∵a=2,b=-5,c=1,
△=b2-4ac=(-5)2-4×2×1=17>0,
∴x=
5±
| ||
| 4 |
则x1=
5+
| ||
| 4 |
5-
| ||
| 4 |
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