题目内容
计算:
(1)(
-3
)•
;
(2)2
+3
-
-
;
(3)
+1+
(
-
)+
;
(4)9
÷
×
;
(5)
•(-
)÷3
.
(1)(
|
3 |
6 |
(2)2
12 |
1
|
5
|
2 |
3 |
48 |
(3)
2 |
3 |
3 |
6 |
8 |
(4)9
45 |
2
|
3 |
2 |
2
|
(5)
2 |
b |
ab5 |
3 |
2 |
a3b |
|
分析:(1)先算乘法,再化成最简二次根式即可.
(2)先最简二次根式,再合并同类二次根式即可.
(3)先算乘法,再合并同类二次根式即可.
(4)把系数和被开方数分别相乘除,再化成最简即可.
(5)把系数和被开方数分别相乘除,再化成最简即可.
(2)先最简二次根式,再合并同类二次根式即可.
(3)先算乘法,再合并同类二次根式即可.
(4)把系数和被开方数分别相乘除,再化成最简即可.
(5)把系数和被开方数分别相乘除,再化成最简即可.
解答:解:(1)(
-3
)•
=
-3
=
-9
;
(2)2
+3
-
-
=4
+2
-
-
=2
;
(3)
+1+
(
-
)+
=
+1+3-3
+2
=4;
(4)9
÷
×
=(9×1×
)
=
×4
=54
;
(5)
•(-
)÷3
=
•(-
)×
=-
=-a2b
.
|
3 |
6 |
=
|
3×6 |
=
3 |
2 |
2 |
(2)2
12 |
1
|
5
|
2 |
3 |
48 |
=4
3 |
3 |
4 |
3 |
3 |
8 |
3 |
3 |
=2
3 |
(3)
2 |
3 |
3 |
6 |
8 |
=
2 |
2 |
2 |
=4;
(4)9
45 |
2
|
3 |
2 |
2
|
=(9×1×
3 |
2 |
45×
|
=
27 |
2 |
3 |
=54
3 |
(5)
2 |
b |
ab5 |
3 |
2 |
a3b |
|
=
2 |
b |
3 |
2 |
1 |
3 |
ab5•a3b•
|
=-
1 |
b |
a5b5 |
=-a2b
ab |
点评:本题考查了二次根式的混合运算的应用,主要考查学生的计算能力.
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