一、选择题(本大题有10个小题,每小题3分,共30分。在每小题给出的四个选项中,只有一项是符合题目要求的)
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1.
-3的相反数是( )
A . 3
B . -3
C .
D .
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2.
(2024七上·上城期末)
被英国《卫报》誉为“新世界七大奇迹”的港珠澳大桥是中国境内一座连接香港,广东珠海和澳门桥隧工程,它是世界上最长的跨海大桥,桥隧全长55000米,其中55000用科学记数法表示为( )
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A . 1个
B . 2个
C . 3个
D . 4个
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A . 0
B . 8
C . 16
D . 8或1
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-
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7.
(2024七上·上城期末)
《增删算法统宗》记载:“有个学生资性好,一部孟子三日了,每日增法添一倍多,问君每日读多少?”其大意是:有个学生天资聪慧,三天读完一部《孟子》,每天阅读的字数是前一人的两倍.问他每天各读多少个子?已知《孟子》一书共有34685个字,设他第一天读
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmi%3Ex%3C%2Fmi%3E%3C%2Fmath%3E)
个字,则下面所列方程正确的是( )
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-
A . -3
B . -2
C . -1
D . 0
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10.
(2024七上·达川期中)
已知:
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmi%3Em%3C%2Fmi%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmfrac%3E%3Cmrow%3E%3Cmn%3E%7C%3C%2Fmn%3E%3Cmi%3Ea%3C%2Fmi%3E%3Cmo%3E%2B%3C%2Fmo%3E%3Cmi%3Eb%3C%2Fmi%3E%3Cmn%3E%7C%3C%2Fmn%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmi%3Ec%3C%2Fmi%3E%3C%2Fmrow%3E%3C%2Fmfrac%3E%3Cmo%3E%2B%3C%2Fmo%3E%3Cmfrac%3E%3Cmrow%3E%3Cmn%3E2%3C%2Fmn%3E%3Cmn%3E%7C%3C%2Fmn%3E%3Cmi%3Eb%3C%2Fmi%3E%3Cmo%3E%2B%3C%2Fmo%3E%3Cmi%3Ec%3C%2Fmi%3E%3Cmn%3E%7C%3C%2Fmn%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmi%3Ea%3C%2Fmi%3E%3C%2Fmrow%3E%3C%2Fmfrac%3E%3Cmo%3E%2B%3C%2Fmo%3E%3Cmfrac%3E%3Cmrow%3E%3Cmn%3E3%3C%2Fmn%3E%3Cmn%3E%7C%3C%2Fmn%3E%3Cmi%3Ec%3C%2Fmi%3E%3Cmo%3E%2B%3C%2Fmo%3E%3Cmi%3Ea%3C%2Fmi%3E%3Cmn%3E%7C%3C%2Fmn%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmi%3Eb%3C%2Fmi%3E%3C%2Fmrow%3E%3C%2Fmfrac%3E%3C%2Fmath%3E)
, 且abc>0,a+b+c=0.则m共有x个不同的值,若在这些不同的m值中,最大的值为y,则x+y=( )
A . 4
B . 3
C . 2
D . 1
二、填空题(本大题有6个小题,每小题4分,共24分)
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-
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-
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15.
设有理数a,b,c满足a+b+c=0,abc> 0,则a,b,c中正数的个数为
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16.
(2024七上·上城期末)
一只昆虫从点
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmi%3EA%3C%2Fmi%3E%3C%2Fmath%3E)
处出发,以每分钟2米的速度在一条直线上运动,它先前进1米,再后退2米,又前进3米,再后退4米,
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmtext%3E%E2%8B%AF%3C%2Fmtext%3E%3C%2Fmath%3E)
依此规律继续走下去,则运动1小时这只昆虫与
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmi%3EA%3C%2Fmi%3E%3C%2Fmath%3E)
点相距
米.
三、解答题(本大题有7小题,共66分,解答应写出文字说明、证明过程或演算步骤)
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-
(1)
-
(2)
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-
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(1)
在下面带有箭头的直线上先确定好原点以及单位长度,然后在所得的数轴上把下列各数表示出来:
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmo%3E%E2%88%92%3C%2Fmo%3E%3Cmn%3E2%3C%2Fmn%3E%3Cmn%3E++%EF%BC%8C+%3C%2Fmn%3E%3Cmn%3E3%3C%2Fmn%3E%3Cmn%3E.%3C%2Fmn%3E%3Cmn%3E5%3C%2Fmn%3E%3Cmn%3E++%EF%BC%8C+%3C%2Fmn%3E%3Cmo%3E%E2%88%92%3C%2Fmo%3E%3Cmn%3E1%3C%2Fmn%3E%3Cmfrac%3E%3Cmrow%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmfrac%3E%3Cmn%3E++%EF%BC%8C+%3C%2Fmn%3E%3Cmn%3E2%3C%2Fmn%3E%3Cmn%3E.%3C%2Fmn%3E%3Cmn%3E7%3C%2Fmn%3E%3Cmn%3E5%3C%2Fmn%3E%3Cmn%3E++%EF%BC%8C+%3C%2Fmn%3E%3Cmn%3E2%3C%2Fmn%3E%3Cmfrac%3E%3Cmrow%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E3%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmfrac%3E%3Cmn%3E++%EF%BC%8C+%3C%2Fmn%3E%3Cmo%3E%E2%88%92%3C%2Fmo%3E%3Cmn%3E3%3C%2Fmn%3E%3C%2Fmath%3E)
.
![](//tikupic.21cnjy.com/2023/04/24/62/e4/62e4daeb0fa1e299629aba406ce701ee_m.png)
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20.
(2024七上·上城期末)
定义:如果两个一元一次方程的解之和为1,我们就称这两个方程为“和谐方程”.例如:方程
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E4%3C%2Fmn%3E%3Cmi%3Ex%3C%2Fmi%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E8%3C%2Fmn%3E%3C%2Fmath%3E)
和
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmi%3Ex%3C%2Fmi%3E%3Cmo%3E%2B%3C%2Fmo%3E%3Cmn%3E1%3C%2Fmn%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E0%3C%2Fmn%3E%3C%2Fmath%3E)
为“和谐方程”.
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(1)
若关于
x的方程
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E3%3C%2Fmn%3E%3Cmi%3Ex%3C%2Fmi%3E%3Cmo%3E%2B%3C%2Fmo%3E%3Cmi%3Em%3C%2Fmi%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E0%3C%2Fmn%3E%3C%2Fmath%3E)
与方程
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E4%3C%2Fmn%3E%3Cmi%3Ex%3C%2Fmi%3E%3Cmo%3E%E2%88%92%3C%2Fmo%3E%3Cmn%3E2%3C%2Fmn%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmi%3Ex%3C%2Fmi%3E%3Cmo%3E%2B%3C%2Fmo%3E%3Cmn%3E1%3C%2Fmn%3E%3Cmn%3E0%3C%2Fmn%3E%3C%2Fmath%3E)
是“和谐方程”,求
m的值;
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(2)
若关于
x的两个方程
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmfrac%3E%3Cmrow%3E%3Cmi%3Ex%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E3%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmfrac%3E%3Cmo%3E%2B%3C%2Fmo%3E%3Cmi%3Em%3C%2Fmi%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E0%3C%2Fmn%3E%3C%2Fmath%3E)
与
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmfrac%3E%3Cmrow%3E%3Cmn%3E3%3C%2Fmn%3E%3Cmi%3Ex%3C%2Fmi%3E%3Cmo%3E%E2%88%92%3C%2Fmo%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E5%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmfrac%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmfrac%3E%3Cmrow%3E%3Cmi%3Ex%3C%2Fmi%3E%3Cmo%3E%2B%3C%2Fmo%3E%3Cmi%3Em%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmfrac%3E%3C%2Fmath%3E)
是“和谐方程,求
m的值.
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21.
(2024七上·上城期末)
第24届冬奥会于2022年2月4日在北京举行,某经销商在冬奥会前预测带有“冰墩墩”吉祥物标志的甲、乙两种纪念品可能会畅销,于是,该经销商用6 200元一次性购进了甲、乙两种纪念品共100件.已知甲、乙两种纪念品的进价和售价如表:
种类 | 进价(元/件) | 售价(元/件) |
甲 | 50 | 100 |
乙 | 70 | 90 |
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(1)
该经销商一次性购进甲、乙两种纪念品各多少件?
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(2)
如果在北京冬奥会开幕式当天销售完全部纪念品,则可获得利润为多少元?
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(3)
根据预测的销售情况,该经销商会再次以相同的进价购进甲、乙两种纪念品,已知甲种纪念品的数量是第一次购进甲种纪念品数量的2倍,乙种纪念品的数量与第一次所购乙种纪念品数量相同.如果甲种纪念品打折销售,乙种纪念品按原价销售,全部销售完后所获的利润正好比第一次获得的利润多1 200元,则甲种纪念品应按原价打几折销售?
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22.
(2024七上·上城期末)
如图所示,点P是线段AB上任意一点,AB=12 cm,C,D两点分别从点P,B同时向点A运动,且点C的运动速度为2 cm/s,点D的运动速度为3 cm/s,运动时间为t s.
![](//tikupic.21cnjy.com/2024/03/19/8c/67/8c676e14a6f08945bcf5a1f9074a88b3_m_251x53.jpg)
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(1)
若AP=8 cm:
①两点运动1 s后,求CD的长;
②当点D在线段PB上运动时,试说明:AC=2CD;
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(2)
当t=2时,CD=1 cm,试探索AP的长.
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(1)
如图1,求证:
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmo%3E%E2%88%A0%3C%2Fmo%3E%3Cmi%3EA%3C%2Fmi%3E%3Cmi%3EO%3C%2Fmi%3E%3Cmi%3EB%3C%2Fmi%3E%3Cmo%3E%E2%88%92%3C%2Fmo%3E%3Cmo%3E%E2%88%A0%3C%2Fmo%3E%3Cmi%3EE%3C%2Fmi%3E%3Cmi%3EO%3C%2Fmi%3E%3Cmi%3EB%3C%2Fmi%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmo%3E%E2%88%A0%3C%2Fmo%3E%3Cmi%3ED%3C%2Fmi%3E%3Cmi%3EO%3C%2Fmi%3E%3Cmi%3EE%3C%2Fmi%3E%3C%2Fmath%3E)
;
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(2)
如图2,作OF平分∠AOB,求证:
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmtext%3E%E2%88%A0%3C%2Fmtext%3E%3Cmtext%3EE%3C%2Fmtext%3E%3Cmtext%3EO%3C%2Fmtext%3E%3Cmtext%3EF%3C%2Fmtext%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmfrac%3E%3Cmrow%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmfrac%3E%3Cmtext%3E%E2%88%A0%3C%2Fmtext%3E%3Cmtext%3ED%3C%2Fmtext%3E%3Cmtext%3EO%3C%2Fmtext%3E%3Cmtext%3EB%3C%2Fmtext%3E%3C%2Fmath%3E)
;
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(3)
如图3,在(2)的条件下,当∠AOD=90°时,作射线OA的反向延长线OC,OH在OA的下方,且∠AOH=∠AOE,反向延长射线OE得到射线OQ,射线OP在∠HOQ内部,OG是∠EOP的平分线,若∠BOC-∠DOF=26°,5∠GOH-2∠POQ-∠EOF=71°,求∠BOP的度数.