题目内容
(1)化简:(
+
)÷
•
(2)解方程组
.
| b | ||
|
| a | ||
|
| ab | ||||
|
| a-b | ||||
|
(2)解方程组
|
(1)原式=(
+
)•
•
,
=(
+
)•
,
=
•
,
=
;
(2)
,
①×2得:2x2-6xy+4y2+8x+6y-2=0,③
③-②得;3y2+4y+1=0,
解得:y1=-1,y2=-
,
把y1=-1代入①得:x2+7x-2=0,
解得:x1=
,x2=
,
把y2=-
代入①得:x2+5x-
=0,
解得:x1=-
,x2=
,
∴方程组的解为
,
,
,
.
| ||||||
|
| ||||||
|
| ||||
| ab |
| a-b | ||||
|
=(
| ||||
|
| ||||
|
| a-b |
| ab |
=
b-
| ||||
| b-a |
| a-b |
| ab |
=
| -a-b |
| ab |
(2)
|
①×2得:2x2-6xy+4y2+8x+6y-2=0,③
③-②得;3y2+4y+1=0,
解得:y1=-1,y2=-
| 1 |
| 3 |
把y1=-1代入①得:x2+7x-2=0,
解得:x1=
7+
| ||
| 2 |
7-
| ||
| 2 |
把y2=-
| 1 |
| 3 |
| 16 |
| 9 |
解得:x1=-
| 16 |
| 3 |
| 1 |
| 3 |
∴方程组的解为
|
|
|
|
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