题目内容
(1)x2-2x-3=0
(2)2x2+5x-1=0
(3)(2x-3)2-121=0
(4)(x-3)2=2(3-x)
(2)2x2+5x-1=0
(3)(2x-3)2-121=0
(4)(x-3)2=2(3-x)
(1)(x-3)(x+1)=0,
x-3=0或x+1=0,
所以x1=3,x2=-1;
(2)△=52-4×2×1=17,
x=
,
所以x1=
,x2=
;
(3)(2x-3)2=121,
2x-3=±11,
所以x1=7,x2=-4;
(4)(x-3)2+2(x-3)=0,
(x-3)(x-3+2)=0,
x-3=0或x-3+2=0,
所以x1=3,x2=1.
x-3=0或x+1=0,
所以x1=3,x2=-1;
(2)△=52-4×2×1=17,
x=
-5±
| ||
2×2 |
所以x1=
-5+
| ||
4 |
-5-
| ||
4 |
(3)(2x-3)2=121,
2x-3=±11,
所以x1=7,x2=-4;
(4)(x-3)2+2(x-3)=0,
(x-3)(x-3+2)=0,
x-3=0或x-3+2=0,
所以x1=3,x2=1.
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