1 . 阅读下面的材料并解答后面所给出的问题:
①
,②![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f075d6404ded0af2ae0540aa3cbe556.png)
两个含二次根式的代数式相乘,若它们的积不含有二次根式,我们就说这两个代数式互为有理化因式,例如:
与
,
与
,数学上将上述把分母变成有理数(式)的过程称为分母有理化,因此,化简一个分母含有二次根式的式子时采用分母、分子同时乘以分母的有理化因式的方法就行了.
(1)
的有理化因式是_________,
的有理化因式是_________.
(2)求
的值;
(3)求
的值.
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31948016d3d90e1b5cd8ec835db46fb5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f075d6404ded0af2ae0540aa3cbe556.png)
两个含二次根式的代数式相乘,若它们的积不含有二次根式,我们就说这两个代数式互为有理化因式,例如:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1f190b17530d81d927c358ac84757a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c34e01955f8c8fe2f0041b35d8d602a7.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2967337e3fcb228dded64ab0c41a17e0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a581f283460235482116fbe3ba41efe.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7bc71a710cce5fb1d9ebc7a831ffbcb.png)
(3)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f9ba395adf869572ade2a849204cf93.png)
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2 . 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“幸运数”.如:
,
,
,因此4,12,20都是“幸运数”.
(1)请判断:36_____“幸运数”;(填“是”或“不是”)
(2)下面是两个同学演算后的发现,请判断真假,并说明理由.
①佳佳发现:两个连续偶数
和
(其中k取非负整数)构造的“幸运数”也是4的倍数.
②琪琪发现:2024是“幸运数”.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d97db6e217a9401024dd82ced228854.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/909caba17c1e14ff9893e40978f2a2ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e834429fa22b6511cfbcee77b8a06d10.png)
(1)请判断:36_____“幸运数”;(填“是”或“不是”)
(2)下面是两个同学演算后的发现,请判断真假,并说明理由.
①佳佳发现:两个连续偶数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a50b6c2fb850cb6699ca261a12ab94f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b5631bc01b998a4b3fabd9e131699dc.png)
②琪琪发现:2024是“幸运数”.
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名校
3 . 算式
的个位数字为__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6505234c04f94047533861b6686f571e.png)
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4 . 先化简,再求值:
,其中
,
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0a6238a59cf9712769d2c340d2465bc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7aaf740a6dfe1cbafc0903fb30740224.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f06408895febc126c2ae409e807349c.png)
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5 . 计算:
(1)
;
(2)
.
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae003aa6547fc543c911d7af57754f11.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96022b167585cb90f079cdf906a2cdd0.png)
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6 . 计算:
(1)
;
(2)
.
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff133e563729a91d09e0cdc115f7183f.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08bcb63cfb7a1c3aa1b47730d278a064.png)
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2024七年级下·浙江·专题练习
7 . 先化简再求值:
(1)
,其中
;
(2)
,其中
.
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/724912a89f34ed128d8a856b26608de0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/707ea658f3a9359f5740d5aab48f7948.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e51380e721b9d55010e4c7c12204006d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6b4707e621f172d717e161057ce5e24.png)
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8 . 如果一个数等于两个连续奇数的平方差,那么我们称这个数为“和谐数”,如:因为
,所以称40为“和谐数”,下面4个数中为“和谐数”的是( ).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af66112e77fc3f7d16e9a25b7bdcb9b6.png)
A.2021 | B.2022 | C.2023 | D.2024 |
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9 . 计算:
(1)
;
(2)
;
(3)
;
(4)
;
(5)
;
(6)
.
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d589415c4e08e8d2e96f644b0aec9ef9.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f820873efa6f6477ea9e2a0feab12e6.png)
(3)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c64498496e287f85e66722049dd8bfe5.png)
(4)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1d7e4f848c3e826cc951bffd50b6027.png)
(5)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0329f083b2090807ea0858e443593347.png)
(6)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f4a0f9a20cd2d5c9f09dd47610dc1897.png)
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10 . 先化简再求值:
其中
,
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ca62d549bae90777826413dbafec2ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b384412acba251d87902ab928902f16.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eefa44964db83759aff6fc8dd7ef8f28.png)
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