题目内容
(1)先化简,再求值:
÷
+
,其中x=2
+1;
(2)解方程组
.
| x-4 |
| x2-1 |
| x2-3x-4 |
| x2+2x+1 |
| 1 |
| x-1 |
| 3 |
(2)解方程组
|
(1)原式=
÷
+
=
×
+
=
,
当x=2
+1时,原式
=
=
=
;
(2)①+②得,5x=10,
∴x=2,
把x=2代入①得,2×2-y=3,
∴y=1,
∴原方程组得解为
.
| x-4 |
| (x+1)(x-1) |
| (x-4)(x+1) |
| (x+1)2 |
| 1 |
| x-1 |
=
| x-4 |
| (x+1)(x-1) |
| (x+1)2 |
| (x-4)(x+1) |
| 1 |
| x-1 |
=
| 2 |
| x-1 |
当x=2
| 3 |
| 2 |
| x-1 |
| 2 | ||
2
|
| 1 | ||
|
| ||
| 3 |
(2)①+②得,5x=10,
∴x=2,
把x=2代入①得,2×2-y=3,
∴y=1,
∴原方程组得解为
|
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