1 . 先化简,再求值:
,其中
,
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c8f3f81232d5627386dccfd822b8343.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b550ee821ee1838384835e81fc34b67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f06408895febc126c2ae409e807349c.png)
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2024-06-10更新
|
243次组卷
|
2卷引用:江苏省江阴市澄要片2023-2024学年七年级下学期期中考试数学试题
2 . 与几何证明一样,代数推理也需要有理有据.请先完成第(1)题的填空,再完成第(2)题的证明.
(1)已知实数x,y满足
,求证
.
证明:∵
,
∴
(实数的加法法则),
(不等式的基本性质1).
∴
(①).
∵
(②),
∴
.
∴
(③).
(2)已知实数x,y满足
,求证
.(注:无需写出每步的依据.)
(1)已知实数x,y满足
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d229cbec798c9c278a9b5979cb38247.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba8073266cfa99b04190473d16b615a8.png)
证明:∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d229cbec798c9c278a9b5979cb38247.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6fa0bb61ce60310f18cb95bf2e83c8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdb9873dfaf15e799fa6fb0128433725.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be487f86d23ca6027e19c8fccc5aa992.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c61f51f0956345e4381e4a86982c551.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43db43c7452258a0d37f8b9ee9c69180.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba8073266cfa99b04190473d16b615a8.png)
(2)已知实数x,y满足
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d229cbec798c9c278a9b5979cb38247.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d168aaaa03c5eeff1b2ebdd688346af6.png)
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3 . 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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4 . (1)计算:
(2)化简:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/469b33f4a369b57c0b5ec84b03a91c4c.png)
(2)化简:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b791ea315c91d3a99a25ef9618e4b90.png)
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5 . 下列运算正确的是( )
A.![]() | B.![]() |
C.![]() | D.![]() |
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6 . 计算或化简:
(1)
;
(2)
.
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b44fbe3594440b748308fdfac3d1aa4.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1dd3ead5a8716f3cf60b8d660157134.png)
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7 . 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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2024七年级下·江苏·专题练习
8 . 计算:
(1)
;
(2)
.
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cbec0fe003e02670c23c14fb90c4afd5.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5b3440f4c54cfb421ae1800422b52e2.png)
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2024八年级下·江苏·专题练习
9 . 计算:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2a1c616497fae4c66f61beff691edc4.png)
______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2a1c616497fae4c66f61beff691edc4.png)
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10 . 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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