题目内容
(1)a-2b2•(a2b-2)-3 (2)(
-
)2-4
(3)
-3×(-
)-2-(
-3)0 (4)
-
(5)( -
)2• (-
)3÷(-
)2 (6)
÷(a-
).
| 5 |
| 2 |
| 10 |
(3)
| 8 |
| 1 |
| 3 |
| 20 |
| 5y+2x |
| y2-x2 |
| 3y |
| y2- x2 |
(5)( -
| a |
| 2b |
| b |
| a |
| b |
| 2a |
| a-b |
| a |
| 2ab-b2 |
| a |
分析:(1)根据负整数指数幂和整数指数幂的公式计算即可,
(2)根据完全平方公式计算,再合并同类二次根式即可,
(3)把二次根式化为最简二次根式,再根据根据负整数指数幂和零指数幂的公式计算即可,
(4)先把分子分母因式分解,再约分即可,
(5)先算乘方,再约分即可,
(6)先算括号里面的,再约分即可,
(2)根据完全平方公式计算,再合并同类二次根式即可,
(3)把二次根式化为最简二次根式,再根据根据负整数指数幂和零指数幂的公式计算即可,
(4)先把分子分母因式分解,再约分即可,
(5)先算乘方,再约分即可,
(6)先算括号里面的,再约分即可,
解答:解:(1)a-2b2•(a2b-2)-3=a-8b8=
(2)(
-
)2-4
=5-2
+2-4
=7-6
;
(3)
-3×(-
)-2-(
-3)0=2
-3×9-1=2
-28;
(4)
-
=
=
=
;
(5)( -
)2• (-
)3÷(-
)2
=
•(-
) •
=-
;
(6)
÷(a-
)
=
÷(
)
=
•
=
.
| b8 |
| a 8 |
(2)(
| 5 |
| 2 |
| 10 |
| 10 |
| 10 |
| 10 |
(3)
| 8 |
| 1 |
| 3 |
| 20 |
| 2 |
| 2 |
(4)
| 5y+2x |
| y2-x2 |
| 3y |
| y2- x2 |
| 5Y+2x-3y |
| y2-x2 |
| 2(y+x) |
| (y+x)(y-x) |
| 2 |
| y-x |
(5)( -
| a |
| 2b |
| b |
| a |
| b |
| 2a |
=
| a 2 |
| 4b 2 |
| b 3 |
| a 3 |
| 4a 2 |
| b 2 |
=-
| a |
| b |
(6)
| a-b |
| a |
| 2ab-b2 |
| a |
=
| a-b |
| a |
| a 2-2ab-b2 |
| a |
=
| a-b |
| a |
| a |
| (a-b) 2 |
=
| 1 |
| a-b |
点评:本题主要考查分式的混合运算,通分、因式分解和约分是解答的关键.
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