题目内容
(1)计算:(-1)2012-|1-6tan30°|-(-
)0+
;
(2)解方程组:
;
(3)先化简,再求值:
÷
-
,其中x=-
,y=-1.
5 |
12 |
(2)解方程组:
|
(3)先化简,再求值:
x-y |
x+3y |
x2-y2 |
x2+6xy+9y2 |
3y |
x+y |
1 |
2 |
(1)(-1)2012-|1-6tan30°|-(-
)0+
=1-(2
-1)-1+2
=1;
(2)
,
由①×2得:4x-2y=-10,③,
③+②得:7x=-14,
x=-2,
把x=-2代入①得:y=1,
所以方程组的解是
.
(3)
÷
-
=
×
-
=
-
=
,
把x=-
,y=-1代入上式得:
=
.
5 |
12 |
=1-(2
3 |
3 |
=1;
(2)
|
由①×2得:4x-2y=-10,③,
③+②得:7x=-14,
x=-2,
把x=-2代入①得:y=1,
所以方程组的解是
|
(3)
x-y |
x+3y |
x2-y2 |
x2+6xy+9y2 |
3y |
x+y |
=
x-y |
x+3y |
(x+3y)2 |
(x+y)(x-y) |
3y |
x+y |
=
x+3y |
x+y |
3y |
x+y |
=
x |
x+y |
把x=-
1 |
2 |
-
| ||
-
|
1 |
3 |
练习册系列答案
相关题目