题目内容
解方程(1)2x2-4x-10=0 (用配方法) (2)2x2+3x=4(公式法)
(3)(x-2)2=2(x-2) (4)
x2+3x-2
=0
(3)(x-2)2=2(x-2) (4)
| 2 |
| 2 |
(1)移项,两边同除2,得x2-2x=5,
配方,得x2-2x+1=6,
即(x-1)2=6,
两边开平方,得x-1=±
,
即x1=1+
,x1=1-
;
(2)移项,得2x2+3x-4=0,
△=32-4×2×(-4)=41,
∴x1=
,x2=
;
(3)移项,得)(x-2)2-2(x-2)=0,
提公因式,得(x-2)(x-2-2)=0,
解得x1=2,x2=4;
(4)因式分解,得(
x-1)(x+2
)=0,
解得x1=
,x2=-2
.
配方,得x2-2x+1=6,
即(x-1)2=6,
两边开平方,得x-1=±
| 6 |
即x1=1+
| 6 |
| 6 |
(2)移项,得2x2+3x-4=0,
△=32-4×2×(-4)=41,
∴x1=
-3+
| ||
| 4 |
-3-
| ||
| 4 |
(3)移项,得)(x-2)2-2(x-2)=0,
提公因式,得(x-2)(x-2-2)=0,
解得x1=2,x2=4;
(4)因式分解,得(
| 2 |
| 2 |
解得x1=
| ||
| 2 |
| 2 |
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