一、选择题(在下列各题的四个选项中,只有一项是符合题意的,请在答题卡中填涂符合题意的选项,本大题共10个小题,每小题3分,共30分)
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1.
(2024九上·衡阳开学考)
芝麻被称为“八谷之冠”,是世界上最古老的油料作物之一,它作为食物和药物,得到广泛的使用,经测算,一粒芝麻的质量约为
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmn%3E0.000000201%3C%2Fmn%3E%3Cmtext%3Ekg%3C%2Fmtext%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
, 将
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmn%3E0.000000201%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
用科学记数法表示为( )
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4.
(2024九上·雁峰开学考)
冬季来临,某同学对甲、乙、丙、丁四个菜市场第四季度的白菜价格进行调查.四个菜市第四个季度白菜的平均值均为2.50元,方差分别为S
甲2=18.3,S
乙2=17.4,S
丙2=20.1,S
丁2=12.5.第四季度白菜价格最稳定的菜市场是( ).
A . 甲
B . 乙
C . 丙
D . 丁
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A . 图象分布在第二、四象限
B . y的值随x值的增大而减小
C . 当x>﹣2时,y<﹣3
D . 点(1,6)和点(6,1)都在该图象上
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7.
(2024九上·雁峰开学考)
已知下列命题:
①对角线互相平分的四边形是平行四边形;②对角线相等的平行四边形是矩形;③对角线互相垂直的四边形是菱形;④对角线垂直且相等的四边形是正方形,其中真命题有( )
A . 1个
B . 2个
C . 3个
D . 4个
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二、填空题(本大题共8个小题,每小题3分,共24分)
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18.
(2024九上·衡阳开学考)
如图,在平面直角坐标系中,直线
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmi%3El%3C%2Fmi%3E%3Cmo%3E%3A%3C%2Fmo%3E%3Cmi%3Ey%3C%2Fmi%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmi%3Ex%3C%2Fmi%3E%3Cmo%3E%E2%88%92%3C%2Fmo%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
与
![](//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)
轴交于点
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsub%3E%3Cmi%3EA%3C%2Fmi%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmsub%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
, 以
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmi%3EO%3C%2Fmi%3E%3Cmsub%3E%3Cmi%3EA%3C%2Fmi%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmsub%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
为一边作正方形
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmi%3EO%3C%2Fmi%3E%3Cmsub%3E%3Cmi%3EA%3C%2Fmi%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmsub%3E%3Cmsub%3E%3Cmi%3EB%3C%2Fmi%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmsub%3E%3Cmsub%3E%3Cmi%3EC%3C%2Fmi%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmsub%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
, 使得点
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsub%3E%3Cmi%3EC%3C%2Fmi%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmsub%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
在
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmi%3Ey%3C%2Fmi%3E%3C%2Fmath%3E)
轴正半轴上,延长
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsub%3E%3Cmi%3EC%3C%2Fmi%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmsub%3E%3Cmsub%3E%3Cmi%3EB%3C%2Fmi%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmsub%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
交直线于点
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsub%3E%3Cmi%3EA%3C%2Fmi%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmsub%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
, 按同样方法依次作正方形
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsub%3E%3Cmi%3EC%3C%2Fmi%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmsub%3E%3Cmsub%3E%3Cmi%3EA%3C%2Fmi%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmsub%3E%3Cmsub%3E%3Cmi%3EB%3C%2Fmi%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmsub%3E%3Cmsub%3E%3Cmi%3EC%3C%2Fmi%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmsub%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
、正方形
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsub%3E%3Cmi%3EC%3C%2Fmi%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmsub%3E%3Cmsub%3E%3Cmi%3EA%3C%2Fmi%3E%3Cmn%3E3%3C%2Fmn%3E%3C%2Fmsub%3E%3Cmsub%3E%3Cmi%3EB%3C%2Fmi%3E%3Cmn%3E3%3C%2Fmn%3E%3C%2Fmsub%3E%3Cmsub%3E%3Cmi%3EC%3C%2Fmi%3E%3Cmn%3E3%3C%2Fmn%3E%3C%2Fmsub%3E%3Cmo%3E%E2%8B%85%3C%2Fmo%3E%3Cmo%3E%E2%8B%85%3C%2Fmo%3E%3Cmo%3E%E2%8B%85%3C%2Fmo%3E%3Cmo%3E%E3%80%81%3C%2Fmo%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
正方形
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsub%3E%3Cmi%3EC%3C%2Fmi%3E%3Cmrow%3E%3Cmi%3En%3C%2Fmi%3E%3Cmo%3E%E2%88%92%3C%2Fmo%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3Cmsub%3E%3Cmi%3EA%3C%2Fmi%3E%3Cmi%3En%3C%2Fmi%3E%3C%2Fmsub%3E%3Cmsub%3E%3Cmi%3EB%3C%2Fmi%3E%3Cmi%3En%3C%2Fmi%3E%3C%2Fmsub%3E%3Cmsub%3E%3Cmi%3EC%3C%2Fmi%3E%3Cmi%3En%3C%2Fmi%3E%3C%2Fmsub%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
, 使得点
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsub%3E%3Cmi%3EA%3C%2Fmi%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmsub%3E%3Cmo%3E%E3%80%81%3C%2Fmo%3E%3Cmsub%3E%3Cmi%3EA%3C%2Fmi%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmsub%3E%3Cmo%3E%E3%80%81%3C%2Fmo%3E%3Cmsub%3E%3Cmi%3EA%3C%2Fmi%3E%3Cmn%3E3%3C%2Fmn%3E%3C%2Fmsub%3E%3Cmo%3E%E3%80%81%3C%2Fmo%3E%3Cmo%3E%E2%8B%85%3C%2Fmo%3E%3Cmo%3E%E2%8B%85%3C%2Fmo%3E%3Cmo%3E%E2%8B%85%3C%2Fmo%3E%3Cmsub%3E%3Cmi%3EA%3C%2Fmi%3E%3Cmi%3En%3C%2Fmi%3E%3C%2Fmsub%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
均在直线
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmi%3El%3C%2Fmi%3E%3C%2Fmath%3E)
上,点
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsub%3E%3Cmi%3EC%3C%2Fmi%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmsub%3E%3Cmo%3E%E3%80%81%3C%2Fmo%3E%3Cmsub%3E%3Cmi%3EC%3C%2Fmi%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmsub%3E%3Cmo%3E%E3%80%81%3C%2Fmo%3E%3Cmsub%3E%3Cmi%3EC%3C%2Fmi%3E%3Cmn%3E3%3C%2Fmn%3E%3C%2Fmsub%3E%3Cmo%3E%E3%80%81%3C%2Fmo%3E%3Cmo%3E%E2%8B%85%3C%2Fmo%3E%3Cmo%3E%E2%8B%85%3C%2Fmo%3E%3Cmo%3E%E2%8B%85%3C%2Fmo%3E%3Cmsub%3E%3Cmi%3EC%3C%2Fmi%3E%3Cmi%3En%3C%2Fmi%3E%3C%2Fmsub%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
在
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmi%3Ey%3C%2Fmi%3E%3C%2Fmath%3E)
轴正半轴上,则点
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsub%3E%3Cmi%3EB%3C%2Fmi%3E%3Cmrow%3E%3Cmn%3E2024%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
的横坐标是
.
![](//tikupic.21cnjy.com/ct20241o/17/51/1751b67b4ed8352461bb4cb36e058daf.png)
三、解答题(本大题共8个小题,第19、20题每题6分,第21、22题每题8分,第23、24题每题9分,第25、26题每题10分,共66分,解答应写出必要的文字说明、证明过程或演算步骤)
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21.
(2024九上·衡阳开学考)
学校组织七、八年级学生参加了“国家安全知识”测试,已知七、八年级各有
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E200%3C%2Fmn%3E%3C%2Fmath%3E)
人,现从两个年级分别随机抽取
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E10%3C%2Fmn%3E%3C%2Fmath%3E)
名学生的测试成绩(单位:分)进行统计:
七年级:![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E86%3C%2Fmn%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmn%3E94%3C%2Fmn%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmn%3E79%3C%2Fmn%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmn%3E84%3C%2Fmn%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmn%3E71%3C%2Fmn%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmn%3E90%3C%2Fmn%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmn%3E76%3C%2Fmn%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmn%3E83%3C%2Fmn%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmn%3E90%3C%2Fmn%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmn%3E87%3C%2Fmn%3E%3C%2Fmath%3E)
八年级:![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E88%3C%2Fmn%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmn%3E76%3C%2Fmn%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmn%3E90%3C%2Fmn%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmn%3E78%3C%2Fmn%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmn%3E87%3C%2Fmn%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmn%3E93%3C%2Fmn%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmn%3E75%3C%2Fmn%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmn%3E87%3C%2Fmn%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmn%3E87%3C%2Fmn%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmi+mathvariant%3D%22normal%22%3E%26nbsp%3B%3C%2Fmi%3E%3Cmn%3E79%3C%2Fmn%3E%3C%2Fmath%3E)
整理如下:
年级 | 平均数 | 中位数 | 众数 | 方差 |
七年级 | 84 | a | 90 | ![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmn%3E44.4%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
|
八年级 | 84 | 87 | b | ![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmtable+columnalign%3D%22left%22%3E%3Cmtr+columnalign%3D%22left%22%3E%3Cmtd+columnalign%3D%22left%22%3E%3Cmrow%3E%3Cmn%3E36.6%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmtd%3E%3C%2Fmtr%3E%3C%2Fmtable%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
|
根据以上信息,回答下列问题:
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(1)
填空:
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmi%3Ea%3C%2Fmi%3E%3Cmo%3E%3D%3C%2Fmo%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
________,
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmi%3Eb%3C%2Fmi%3E%3Cmo%3E%3D%3C%2Fmo%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
________,A同学说:“这次测试我得了
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E86%3C%2Fmn%3E%3C%2Fmath%3E)
分,位于年级中等偏上水平”,由此可判断他是________年级的学生;
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(2)
学校规定测试成绩不低于
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E85%3C%2Fmn%3E%3C%2Fmath%3E)
分为“优秀”,估计该校这两个年级测试成绩达到“优秀”的学生总人数;
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(1)
求反比例函数
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmi%3Ey%3C%2Fmi%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmfrac%3E%3Cmi%3Ek%3C%2Fmi%3E%3Cmi%3Ex%3C%2Fmi%3E%3C%2Fmfrac%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
与一次函数
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmi%3Ey%3C%2Fmi%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmo%3E%E2%88%92%3C%2Fmo%3E%3Cmn%3E2%3C%2Fmn%3E%3Cmi%3Ex%3C%2Fmi%3E%3Cmo%3E%2B%3C%2Fmo%3E%3Cmi%3Em%3C%2Fmi%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
的表达式;
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(2)
当
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmi%3EO%3C%2Fmi%3E%3Cmi%3ED%3C%2Fmi%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
时,求线段
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmi%3EB%3C%2Fmi%3E%3Cmi%3EC%3C%2Fmi%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
的长.
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23.
(2024九上·衡阳开学考)
如图,在四边形ABCD中,AB=CD,∠ABC的平分线交AD于点E,与CD的延长线交于点F,BC=FC.
![](//tikupic.21cnjy.com/ct20241o/99/65/99659f1ca182d73a2efa26cb47d13f95.png)
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(2)
若AB=5,BC=8,CE⊥AD,求平行四边形ABCD面积.
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24.
(2024九上·雁峰开学考)
随着时代的发展,“直播带货”已经成为当前最为强劲的购物新潮流,因此“直播带货”将成为企业营销变革的新起点. 某企业为开启网络直播带货的新篇章,购买A,B两种型号直播设备.已知A型设备价格是B型设备价格的
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E1%3C%2Fmn%3E%3Cmo%3E.%3C%2Fmo%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmath%3E)
倍,用1800元购买A型设备的数量比用1000元购买B型设备的数量多5台.
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(2)
某平台计划购买两种设备共60台,要求A型设备数量不少于 B型设备数量的一半,设购买A型设备a台,求w与a的函数关系式,并求出最少购买费用.
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(1)
求直线
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsub%3E%3Cmi%3El%3C%2Fmi%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmsub%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
的解析式;
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(2)
如图2,若点P在直线
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsub%3E%3Cmi%3El%3C%2Fmi%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmsub%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
上,过点P作
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmi%3EP%3C%2Fmi%3E%3Cmi%3EQ%3C%2Fmi%3E%3Cmtext%3E%E2%88%A5%3C%2Fmtext%3E%3Cmi%3Ey%3C%2Fmi%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
轴交
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsub%3E%3Cmi%3El%3C%2Fmi%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmsub%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
于点Q,交x轴于点G,使
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsub%3E%3Cmi%3ES%3C%2Fmi%3E%3Cmrow%3E%3Cmo%3E%E2%96%B3%3C%2Fmo%3E%3Cmi%3EP%3C%2Fmi%3E%3Cmi%3EC%3C%2Fmi%3E%3Cmi%3EG%3C%2Fmi%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E2%3C%2Fmn%3E%3Cmsub%3E%3Cmi%3ES%3C%2Fmi%3E%3Cmrow%3E%3Cmo%3E%E2%96%B3%3C%2Fmo%3E%3Cmi%3EQ%3C%2Fmi%3E%3Cmi%3EC%3C%2Fmi%3E%3Cmi%3EG%3C%2Fmi%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
, 求此时P点的坐标;
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(3)
如图3,点P是直线
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsub%3E%3Cmi%3El%3C%2Fmi%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmsub%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
上一动点,点Q是直线
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsub%3E%3Cmi%3El%3C%2Fmi%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmsub%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
上一动点,点E是坐标平面内一点,若以点C、P、Q、E为顶点的四边形为正方形,且
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmi%3EC%3C%2Fmi%3E%3Cmi%3EQ%3C%2Fmi%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
是正方形的边,若存在,请直接写出点Q的坐标.