题目内容
(1)计算:(-2)2-5×
+2sin30°
(2)计算:
÷
-
(3)解方程组:
.
| 1 |
| 5 |
(2)计算:
| a |
| a-1 |
| a2-a |
| a2-1 |
| 1 |
| a-1 |
(3)解方程组:
|
(1)原式=4-1+2×
=4;
(2)原式=
•
-
=
-
=
;
(3)
,
②-①得x=2,
将x=2代入①,得y=-1,
∴原方程组的解为:
.
| 1 |
| 2 |
(2)原式=
| a |
| a-1 |
| (a+1)(a-1) |
| a(a-1) |
| 1 |
| a-1 |
| a+1 |
| a-1 |
| 1 |
| a-1 |
| a |
| a-1 |
(3)
|
②-①得x=2,
将x=2代入①,得y=-1,
∴原方程组的解为:
|
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