1 . 计算:
(1)![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39f7ce247e7916ae16cfd72feb3e7ab6.png)
(2)
.
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39f7ce247e7916ae16cfd72feb3e7ab6.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/776def26a6c70f357688ae501660f456.png)
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2 . 已知
求下列各式的值:
(1)
和
;
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8587573283f0cd1ce2b85671684c5e7e.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20d6fc9b90f370fbb27552876b650f8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18f0281e6bbdbe08beeccb55adf84536.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2f6407cbc1670813405a91e3f8ef9c7.png)
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3 . 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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4 . 计算:
(1)
;
(2)
.
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a498e8324fc0759b8e5a0f8b7417623d.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acf315f973a3f8f0cd0c8c473931d0bc.png)
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5 . (1)计算:
;
(2)解方程:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f7de38aa79c7a5cebc87cbad860d4b4.png)
(2)解方程:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd24a254b71cd4fcbca0fe2913ca939f.png)
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6 . 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
7 . 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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8 . 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)
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9 . 计算:
(1)
;
(2)
.
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8246a4502655a9c59d0e3d8b48065138.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49d28a8d3fd8f32c2b7e6b66c7c7fcf9.png)
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10 . 计算:
(1)
;
(2)
.
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e0b5b2761c96a7c9ee5d75d915b380b.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08a816fd944f0a9bb5f0d97e7427aabe.png)
您最近一年使用:0次
2024-05-23更新
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188次组卷
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4卷引用:暑假作业13 八年级下学期60道计算题专训(6大题型)-【暑假分层作业】2024年八年级数学暑假培优练(苏科版)
(已下线)暑假作业13 八年级下学期60道计算题专训(6大题型)-【暑假分层作业】2024年八年级数学暑假培优练(苏科版)河南省驻马店市西平县多校联考2023-2024学年八年级下学期期中考试数学试题河南省驻马店市西平县2023-2024学年八年级下学期期中数学试题(已下线)第10讲 二次根式的加减【十大考点+过关测】- 【暑假自学课】2024年新八年级数学暑假提升精品讲义(北师大版)