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1 . 已知关于x和y的二元一次方程组
(k为实数),有下列说法:①x和y互为相反数时,
;②
的值与k无关;③若
,则解为
;④若
,k为整数,则k的值为
.以上正确的有( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec39ef4578ce9d3dded6b73c39adc002.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8e69866076dcff686a05e9e91e61e68.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5829cd4256c0516b3fc82e6548c79a12.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d14d8313d88ca7851698bcd469638f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/367e788c32187ae2cc97aaa24da1d40d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1783742701d4301833516d763ad41f31.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b55177754fdfc9b5b4412b5cbc7b6ba.png)
A.1个 | B.2个 | C.3个 | D.4个 |
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2 . 已知
,
.
(1)当
,
时,
的值为__________ ;
(2)若无论
取何值时,
总成立,则
的值为__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3008cdf44ab43740f79df32e92768eb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a73fd1588c47bd3b5e57cd90d997ce9.png)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5ddeddf42507ae9341feb019bb5be33.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e258ab9e600435b37465092243d99f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
(2)若无论
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9129759975eeb05e46fac849ce954a29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
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3 . 定义
,如
.已知
(m为常数),
.
(1)若A的代数式中不含x的一次项,求m的值;
(2)若A中的m满足
,计算
的结果.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c1544d0c9166aadbbc7a005573f3d19.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6791134f1dcc3dcf4458fe7f1eaeca8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a00f32006b7c3aa8554a4339e6ae968.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/702d1a83794da3cff2891343f0ee2fdb.png)
(1)若A的代数式中不含x的一次项,求m的值;
(2)若A中的m满足
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23b7b875e9d0f19780e4ccc8f6874d27.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8df69c6a544f62a016490b012c353ae7.png)
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4 . 有甲、乙两个长方形纸片,边长如图所示
,面积分别记为
和
.
______;
______;
②用“
”,“
”或“
”填空:
______
.
(2)若一个正方形纸片的周长与甲长方形的周长相等,面积为
.
①该正方形的边长是______(用含
的代数式表示);
②小方同学发现:
与
的差与
无关,请判断小方的发现是否正确,并通过计算说明你的理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ac9959eb2a1fd71a0d63e7778ae7229.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b02526771dc5a6d66fb9029bff5eac3b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c4bf6d5a546594c4176867be0ec896b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c468af7fb9d4b1280cc3fafe4bfa1ea7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3aac54cc368cbed074840a2abff2994.png)
②用“
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/392cdb9d30684cce244bef94b8d861b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ff7942da6c3fc4005256fb1458557c0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6706fe00b4e231e62d9ecbec567d526b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b02526771dc5a6d66fb9029bff5eac3b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c4bf6d5a546594c4176867be0ec896b.png)
(2)若一个正方形纸片的周长与甲长方形的周长相等,面积为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69762da0d8c1d563c8a42f371ed20ae3.png)
①该正方形的边长是______(用含
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
②小方同学发现:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69762da0d8c1d563c8a42f371ed20ae3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b02526771dc5a6d66fb9029bff5eac3b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
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5 . 如图,小长方形纸片的长为a,宽为b,且
,将7张纸片按图示不重叠的放在长方形
内,未被覆盖的部分恰好被分割为两个长方形,面积分别为
和
.
时,
的值为_________ ;
(2)若
长度保持不变,
变长,将这7张小长方形纸片还按照同样的方式放在新的长方形
内,当
的值与
的长度无关时,a、b满足的关系式是_________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/432d77fe5ad3032d59a237dd94c8a638.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e097c8d4c948de063796bd19f85b3a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e0bd63f55069a3bc870915010b39225.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0243bea8a3c5dee1f2ebb417abde0982.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16ae89bd2dd0a18e1afb5b1a1abd0efd.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87dd022eba9b0bb75d3c72216c9e93fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
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6 . 知识回顾:七年级学习代数式求值时,遇到过这样一类题“代数式
的值与x的取值无关,求a的值”,通常的解题方法是把x,y看作字母,a看作系数,合并同类项,因为代数式的值与x的取值无关,所以含x项的系数为0,即原式
,所以
,则
.理解应用:若关于x的多项式
的值与x的取值无关,求m的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27f26471fb8dda15eb797b4d436d549d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8dfee97b8f7e463c82bec55c261481f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d20ba18439f01149bdeda640f6748d29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb8e1dd8da540badcb9a8f427c5b202e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6dcea1b48bc40cbaea3af79601d70d3.png)
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7 . 当![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd707b69a11f8de5566f23c1a2a9ff5a.png)
______ 时,关于
的多项式
中不含
项.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd707b69a11f8de5566f23c1a2a9ff5a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b0fffbec1fe851795dfdd448bf0d165.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c140d291b7ed2d246288033d14dee11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f29d5f376c75c41ae6af0c8a8565449.png)
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8 . 已知关于x,y的方程组![](https://staticzujuan.xkw.com/quesimg/Upload/formula/235a7c53503b4ab9d521267b6f1c3fe0.png)
(1)用含m的代数式表示x、y;
(2)若方程组的解也满足方程
,求m的值:
(3)当a、b满足什么条件时,无论m取何值,
是个定值,并求出这个定值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/235a7c53503b4ab9d521267b6f1c3fe0.png)
(1)用含m的代数式表示x、y;
(2)若方程组的解也满足方程
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90ebe770f8bb49093e7317526586a5af.png)
(3)当a、b满足什么条件时,无论m取何值,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0632ee990f336047821147e760bb8368.png)
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名校
9 . 定义:对于依次排列的多项式
、
、
、
(a、b、c、d是常数),当它们满足
,且
是常数时,则称a、b、c、d是一组平衡数,
是该组平衡数的平衡因子.例如,对于多项式
、
、
、
来说,因为
,所以2、1、6、5是一组平衡数,4是这组平衡数的平衡因子.
(1)已知2、4、7、9是一组平衡数,则该组平衡数的平衡因子
______;
(2)若
、2、
、3是一组平衡数,求
的值及该组平衡数的平衡因子;
(3)当a、b、c、
之间满足怎样的数量关系时,它们是一组平衡数,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b677b9db7f77efe2e1f3c5243c173cb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd082ae3d03818ce505e0994b2710a72.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65b8a0d036a618ff7d2368ba86e98ba9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e156fa4bb29ea24931ac3a6e4a885b0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/28de2f512cb37955f3669610bb9381d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39241f2eeccaa16d0550d851619bcb42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73b5a9de8a72dda70e3eefeb0a408ffd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad591b84cbd3ddd92958efb01921198e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f95bde47c11d4c07a2b038414de4d18f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b265c11072194eadd1c0ab1c1ece5482.png)
(1)已知2、4、7、9是一组平衡数,则该组平衡数的平衡因子
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/774aee07dda559e75f4a061d72f6164b.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/395addb4439331615a7f220289d8b62c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
(3)当a、b、c、
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c02bc0c74292b1e8f395f90935d3174.png)
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名校
10 . (1)先化简,再求值:
,其中
,
.
(2)说明代数式
的值与
的值无关.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81b792ded2e21acaa33fdcc1d6e4385f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba53065eb180a682305fddb95d14b62f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1d0aa9412dd7caf42cc71520e282328.png)
(2)说明代数式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/395bbe48e6e00aa3194fb0b7bd79df2c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
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