江苏省徐州市2020-2021学年九年级下学期第一次模拟检测数学试卷参考答案

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九年级数学期中试题参考答案 ( 第 1 页 共 4 页 )
2020—2021 学年度初中、毕业升学第一次模拟检测
九年级数学试题参考答案及评分标准
题号
1
2
3
4
5
6
7
8
选项
C
B
D
D
C
B
A
C
9.
4
10. 2 11.
6x
12. 8 13. －2
14.
12
15. 3 16. 55º 17.
18. 625
19. (1) 原式= 2－4－1 ····················································································· 3 分
=－2－1 ························································································ 4 分
=－3 . ··························································································· 5 分
(2) 原式 =
212
()
( 1) ( 1)
a a a
a a a a

 
·························································· 3 分
=
2
( 1)
( 1) ( 1)
aa
a a a
 
···································································· 4 分
=
1
1
a
a
··························································································· 5 分
20. (1) 解法一：(配方法)
x2－4x + 4 = 2. ························································································· 1 分
(x－2)2=2. ······························································································· 2 分
x－2=
2
. ···························································································· 3 分
x1=2
2
，x2=2
2
. ··············································································· 5 分
解法二：(公式法)
x2－4x + 2 = 0. ························································································· 1 分
∵a=1，b=－4，c =2.
b2－4ac = 16－8 = 8. ················································································· 2 分
∴
22
2
224
12
8)4(
x
··········································· 3 分
∴
.22,22 21
xx
， (结果正确没化简，扣 1分) . ···················· 5 分
(2) 由① 得，x ≤－3， ················································································ 2 分
由② 得，
1
2
x
. ······················································································ 4 分
九年级数学期中试题参考答案 ( 第 2 页 共 4 页 )
所以不等式组的解集是：x ≤－3. ································································· 5 分
21. (1)
1
3
. ···································································································· 2 分
(2) 若王老师、张老师、李老师分别用 A、B、C表示，画树状图如下： ··············· 5 分
共有 9种等可能情况，其中都是王老师测体温的有 1种情况，则都是王老师测体温
的概率是
1
9
． ······················································································ 7 分
22. (1) 100 ； ································································································ 3 分
(2) 补完条形图（如图 ）. ·········································································· 5 分
(3)
%402000
800 . ·········································································· 7 分
23. (1) ∵AB∥CD，∴∠B＝∠D． ····································································· 1 分
在△ABE 和△CDF 中，
BD
AB CD
BAE DCF
 
 
，∴△ABE≌△CDF（ASA）．∴AE＝CF．
············································································································ 4 分
(2) 由（1）△ABE≌△CDF 得∠AEB＝∠CFD ． ·········································· 5 分
∴180°－∠AEB＝180°－∠CFD，
即∠AEF＝∠CFE．∴AE∥CF ． ································································ 7 分
∴四边形 AECF 是平行四边形． ·································································· 8 分
24.（1）设每副围棋 x元，则每副象棋（x﹣8）元． ············································· 1 分
根据题意，得
420 756
8xx
． ········································································· 4 分
解得 x＝18．
经检验 x＝18 是所列方程的根． ·································································· 6 分
所以 x﹣8＝10． ······················································································ 7 分
( 第22 题 ) ( 第21 题 )
江苏省徐州市2020-2021学年九年级下学期第一次模拟检测数学试卷参考答案.pdf

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作者：envi 分类：初中 价格：3知币 属性：4 页 大小：383.48KB 格式：PDF 时间：2025-04-22

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