题目内容
解方程:
(1)x2-6x-28=0(用配方法)
(2)3(x-5)2=2(5-x)
(1)x2-6x-28=0(用配方法)
(2)3(x-5)2=2(5-x)
(1)x2-6x=28,
配方得:x2-6x+9=37,即(x-3)2=37,
开方得:x-3=±
,
解得:x1=3+
,x2=3-
;
(2)3(x-5)2+2(x-5)=0,
(x-5)[3(x-5)+2]=0,
(x-5)(3x-13)=0,
解得:x1=5,x2=
.
配方得:x2-6x+9=37,即(x-3)2=37,
开方得:x-3=±
| 37 |
解得:x1=3+
| 37 |
| 37 |
(2)3(x-5)2+2(x-5)=0,
(x-5)[3(x-5)+2]=0,
(x-5)(3x-13)=0,
解得:x1=5,x2=
| 13 |
| 3 |
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