1 . 先化简,再求值
,其中
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5538bcef820b44820637bc8d8842c3ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c98a7f3a8bf384b1dfc1d34aebd46d2.png)
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2 . 计算:
(1)
;
(2)
;
(3)
;
(4)
.
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fe47766f5db96d4e462237370dba381.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b62d642b93a03b89257641e07e9d2942.png)
(3)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79af3e65bf19acf43568d16f51d736ed.png)
(4)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c693664b2ceeab7350923b332539916f.png)
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3 . 计算:
(1)
;
(2)
;
(3)
.
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c0516e54aa9e75c74b0b06a9b563b26.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6911f37e9c0a50e63af66f77ad428572.png)
(3)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d6f50d5c50051ca3b8831591368f02a.png)
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名校
4 . 已知
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b76a763e16272d3a6e9588c7a8c4ec2.png)
_______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba6ce8a3e77d9b1064f9a6cbf6601e68.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b76a763e16272d3a6e9588c7a8c4ec2.png)
您最近一年使用:0次
2024-06-03更新
|
189次组卷
|
2卷引用:江苏省扬州市江都区邵樊片2023-2024学年七年级下学期期中数学试题
5 . 定义:我们将
与
称为一对“对偶式”.
因为
,可以有效的去掉根号,所以有一些题可以通过构造“对偶式”来解决.
例如:
,所以
与
互为“对偶式”.
(1)
的“对偶式”是________,
的“对偶式”是________.
(2)已知
,其中
.
①
的“对偶式”的值是________.
②利用“对偶式”的相关知识,求方程
中x的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9928ba39cdd5878aced506d3dbb9fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b87033f1efe85e559a9a3efc985be9d.png)
因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/50036f42d68bcb48ee54bf6a8e76856f.png)
例如:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9716b80c5256540830bd48ad968f5d0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e833d2c9f895f404a733a7d389e3b07.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acba2d76c389f6f53cc8cf757760cd02.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77abd3f77c42e53acb598fbc64cc22f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63319272787a2c3137212e4d11b0e887.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/95c3a00640f05c28e85b3d2e2ba562f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44d16f50c58699f352885df1f7bc9132.png)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63319272787a2c3137212e4d11b0e887.png)
②利用“对偶式”的相关知识,求方程
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/95c3a00640f05c28e85b3d2e2ba562f9.png)
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名校
6 . 下列不能用平方差公式运算的是( )
A.![]() | B.![]() |
C.![]() | D.![]() |
您最近一年使用:0次
2024-05-25更新
|
86次组卷
|
2卷引用:江苏省无锡市锡山区锡东片2023-2024学年七年级下学期期中考试数学试题
7 . 如果一个正整数能表示为两个连续偶数的平方差,那么称这个正整数为“神秘数”,如:
,
,
,因此4、12、20 都是“神秘数”.
(1)请说明36是否为“神秘数”;
(2)你能说明“神秘数”一定是4的倍数吗?若能,请说明理由,若不能,请举一个反例.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb8356b858e36e263196abfe717cb5b0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d32f612592f0ec8499a2a74807f6f3a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e834429fa22b6511cfbcee77b8a06d10.png)
(1)请说明36是否为“神秘数”;
(2)你能说明“神秘数”一定是4的倍数吗?若能,请说明理由,若不能,请举一个反例.
您最近一年使用:0次
8 . 计算:
(1)
;
(2)
;
(3)
;
(4)
.
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/410ba12a573f30bddce9a73886ff77b3.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/862a639b2cd93a9145ffc850891a42ed.png)
(3)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff5142f72b6dd6dcd56a370cac983475.png)
(4)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/70488c259c63ff6add89eb691f28c38b.png)
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9 . 如果
能运用平方差公式进行计算,那么m、n满足的条件可能是( )
①
;②
;③
;④
;
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26b73538a833e84268d52411060b1907.png)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be741ec48fdf8b53cea64a142819a5f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73230e1d5cbb9e53e35d1d3eafeb5d3a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d88798ac45ad76cc4bcc310711aabdcd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b5b28028ea0f4d462cf4edd7ba80689.png)
A.①② | B.②③ | C.①④ | D.③④ |
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10 . 先化简,再求值:
,其中
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fca3db10045e24cf57c0c84678bc0943.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b70d392612a67b33ec67cda42b77ce30.png)
您最近一年使用:0次