1 . 观察下列表格中几个代数式及其相应的值,回答问题.
(1)【初步感知】
①根据表中信息可知,
________,
________;
②若
的值比
的值大27.求x的值.
(2)【归纳规律】
表中
的值的变化规律是x的系数是1,x的值每增加1,
的值就增加1;
的值的变化规律是x的系数是2,x的值每增加1,
的值就增加________.类似的,
的值的变化规律是x的系数是
,x的值每增加1,
的值就减少________.
(3)【问题解决】
若关于x的代数式
,当x的值每增加1,
的值就减少5,且当
时,
的值为6,求这个代数式.
x | ![]() | ![]() | ![]() | 0 | 1 | 2 | ![]() |
![]() | ![]() | ![]() | ![]() | ![]() | a | 0 | ![]() |
![]() | ![]() | ![]() | 1 | b | 5 | 7 | ![]() |
![]() | ![]() | 2 | 1 | ![]() | ![]() | 10 | ![]() |
(1)【初步感知】
①根据表中信息可知,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/380bbacf854e30e2e747fc286d2b9997.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ccd4162c7d09f970cb77cadacdbe521.png)
②若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8353952f4ec264d745ab12c055009b67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf755d54cfb9e01fc72e729f323cadcf.png)
(2)【归纳规律】
表中
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38c3fa8692612e51579e3cef22fd8c4b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38c3fa8692612e51579e3cef22fd8c4b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8353952f4ec264d745ab12c055009b67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8353952f4ec264d745ab12c055009b67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf755d54cfb9e01fc72e729f323cadcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81fb134b2b48acc99213fff6ccfee65f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf755d54cfb9e01fc72e729f323cadcf.png)
(3)【问题解决】
若关于x的代数式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cff29c9990fc396010668b2b8afb4dbf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cff29c9990fc396010668b2b8afb4dbf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/707ea658f3a9359f5740d5aab48f7948.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cff29c9990fc396010668b2b8afb4dbf.png)
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2 . 若
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c62d6371f7688d2f33e7b59cddbf5738.png)
_______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/95abcaedb2c875a5a6175387f4ca758c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c62d6371f7688d2f33e7b59cddbf5738.png)
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2024-03-14更新
|
393次组卷
|
2卷引用:四川省成都市天府新区2022-2023学年七年级下学期期末考试数学试题
3 . 一个实数的两个平方根分别是
和
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/380bbacf854e30e2e747fc286d2b9997.png)
______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7084b7c5564061fdd5d65e07f9692d90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4480cb985ee051bac107405b85bae602.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/380bbacf854e30e2e747fc286d2b9997.png)
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4 . 解方程:
(1)
;
(2)
.
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b55abd38d65e1839c726723686cd6490.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6f6d7dd8f3848b9bce75a33c384388c.png)
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5 . 下列各式中:
①由
系数化为1得
;
②由
移项得
;
③由
去分母得
;
④由
去括号得
.其中正确的个数有( )
①由
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f87bcf36ac543c580d86e64a8b304beb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1052381f3cdfd0464f54002717e17d34.png)
②由
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a6e0855d31fa781b3041b396ba49605.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae4f3f3f0e10bd8b332701ff6fab1c85.png)
③由
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f61da0ab62691d94ed64b1d06736ec2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b86b62bfb79e9093ff4ec4ea813cb8a.png)
④由
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5933372da1ea04a17e6a46076d952c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f34726e2c825d15ea30614b96c3c2674.png)
A.4个 | B.2个 | C.1个 | D.0个 |
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6 . 定义:关于
的方程
与方程
(a,b均为不等于0的常数)互为“反对方程”.
例如:方程
与方程
互为“反对方程”.
(1)若方程
与方程
互为“反对方程”,则
__________;
(2)若关于
的方程
与方程
互为“反对方程”,求m,n的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e02448598bbb9d28612fbb68a3d7d2a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/107b8c7c5b3321e555a353c95a1b2a55.png)
例如:方程
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22d230539d4b432e71e8e596960d1400.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f9378f4030a56301dfdf892c0b36182b.png)
(1)若方程
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88dbb9fb86e8c03c3ff5d5b5afe77382.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b99f96ded5a63b03ecd505dc262831bc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f4e9bb42376c12d7d21702ae8062b25a.png)
(2)若关于
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f255aa929eb32ef619fec98555788ec6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4ebca381f083eac569c4e2a730150c9.png)
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7 . (1)计算:
;
(2)解方程:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c89c9c43511d13253e44629df1c3a3d1.png)
(2)解方程:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73a555028353d7fe350ee62192f7c53c.png)
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8 . 已知方程
与关于x的方程
的解相同,则
的值是______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9074efe0658ef43012aef2a5ba9317f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1af785ef0a6d3fda640463f05efbbc8c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4de31f79c12d1ac10a670ae9ce707622.png)
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9 . 解下列方程:
(1)
;
(2)
;
(3)
;
(4)
.
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8e4cf3c9b8afd4fa596db089edb8245.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8429e49cd05b815fac8e9edd8e4c0541.png)
(3)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04fd6c9f4af967764474095217082499.png)
(4)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/40d23c67e511f31fe147fd95e3590065.png)
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10 . 已知方程
的解同时也是方程
的解,则
的值为________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21e4e01c978cd6e789881e60b3dd97cc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/affafc988c29ea98071f505cba048c43.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c7a8c9af365310df4068099e1599271.png)
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