题目内容
(1)计算:9
÷3
-
×
(2)解方程:2(x+2)2=x2-4.
| 45 |
|
3
| ||
|
2
|
(2)解方程:2(x+2)2=x2-4.
(1)9
÷3
-
×
=9
×
-
×
=3
-
=45
-2
=43
;
(2)2(x+2)2=x2-4,
2(x+2)2=(x+2)(x-2),
2(x+2)2-(x+2)(x-2)=0,
(x+2)[2(x+2)-(x-2)]=0,
即(x+2)(x+6)=0,
可化为:x+2=0或x+6=0,
解得:x1=-2,x2=-6.
| 45 |
|
3
| ||
|
2
|
=9
| 45 |
| ||
| 3 |
3
| ||
|
| ||
|
=3
| 450 |
| 8 |
=45
| 2 |
| 2 |
=43
| 2 |
(2)2(x+2)2=x2-4,
2(x+2)2=(x+2)(x-2),
2(x+2)2-(x+2)(x-2)=0,
(x+2)[2(x+2)-(x-2)]=0,
即(x+2)(x+6)=0,
可化为:x+2=0或x+6=0,
解得:x1=-2,x2=-6.
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