题目内容
(1)解方程:x2-2x-1=0;
(2)计算:(3
-2
)2-(3
-2
)(3
+2
)
(2)计算:(3
| 2 |
| 3 |
| 2 |
| 3 |
| 2 |
| 3 |
(1)移项,得:x2-2x=1,
配方:x2-2x+1=2,
即(x-1)2=2,
则x-1=±
,
因而x1=
+1,x2=-
+1;
(2)原式=(3
-2
)[(3
-2
)-(3
+2
)]
=(3
-2
)×(-4
)
=-12
+24.
配方:x2-2x+1=2,
即(x-1)2=2,
则x-1=±
| 2 |
因而x1=
| 2 |
| 2 |
(2)原式=(3
| 2 |
| 3 |
| 2 |
| 3 |
| 2 |
| 3 |
=(3
| 2 |
| 3 |
| 3 |
=-12
| 6 |
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