题目内容
(1)(3
-
-
)÷2
(2)(
+
-
)(
-
+
)
| 75 |
| 12 |
| 27 |
| 3 |
(2)(
| 2 |
| 3 |
| 6 |
| 2 |
| 3 |
| 6 |
分析:(1)先把括号内的二次根式化为最简二次根式,合并后进行二次根式的除法运算;
(2)先变形得到原式=[
+(
-
)][
-(
-
)],再根据平方差公式展开,然后根据完全平方公式进行计算.
(2)先变形得到原式=[
| 2 |
| 3 |
| 6 |
| 2 |
| 3 |
| 6 |
解答:解:原式=(15
-2
-3
)÷2
=10
÷2
=5;
(2)原式=[
+(
-
)][
-(
-
)]
=(
)2-(
-
)2
=2-(3-6
+6)
=2-3+6
-6
=6
-7.
| 3 |
| 3 |
| 3 |
| 3 |
=10
| 3 |
| 3 |
=5;
(2)原式=[
| 2 |
| 3 |
| 6 |
| 2 |
| 3 |
| 6 |
=(
| 2 |
| 3 |
| 6 |
=2-(3-6
| 2 |
=2-3+6
| 2 |
=6
| 2 |
点评:本题考查了二次根式的混合运算:先把各二次根式化为最简二次根式,在进行二次根式的乘除运算,然后合并同类二次根式.
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