内容正文:
2023年江苏苏州中考考前押题密卷
数学·全解全析
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A
9. 10. 11./ 12.1或或3
13. 14. 15.20/二十 16.
17.【答案】0
【分析】根据实数的计算法则,零指数幂和负整数指数幂的计算法则求解即可.
【详解】解:原式····································3分
.····································5分
【点睛】本题主要考查了实数的运算,零指数幂和负整数指数幂,正确计算是解题的关键.
18.【答案】方程无解
【分析】根据解分式方程的一般方法步骤求解,然后检验即可.
【详解】解:
方程两边同乘以去分母得:······································2分
解这个方程得,···································································3分
检验:将代入得,4分
所以,是原方程的增根
∴原方程无解.··········································································5分
【点睛】题目主要考查解分式方程的方法步骤,熟练掌握解分式方程的一般方法步骤是解题关键.
19.【答案】,
【分析】根据平方差公式与单项式乘以单项式进行计算,然后将代入求值即可求解.
【详解】解:原式=
···············································································3分
当时,原式···················································6分
【点睛】本题考查了整式的混合运算,实数的运算,代数式求值,正确的计算是解题的关键.
20.【答案】(1)
(2)
【分析】(1)由三根同样的绳子、、穿过一块木板,直接利用概率公式求解即可求得答案;
(2)利用列举法可得:,,,其中符合题意的有2种、,然后直接利用概率公式求解即可求得答案.
【详解】(1)解:共有三根同样的绳子、、穿过一块木板,
姐姐从这三根绳子中随机选一根,恰好选中绳子的概率为:;
故答案为:;··········································································2分
(2)解:列举得:,,,,,,,,;
共有9种等可能的结果,其中符合题意的有6种,··········································4分
这三根绳子能连接成一根长绳的概率是:.·······································6分
【点睛】此题考查了列举法求概率的知识.用到的知识点为:概率所求情况数与总情况数之比.
21.【答案】(1)见解析
(2)四边形是平行四边形,理由见解析
【分析】(1)由得到,又由即可证明;
(2)由得到,则,即可判断四边形是平行四边形.
【详解】(1)∵,
∴,
即,
∵,
∴;································································3分
(2)如图,连接,四边形是平行四边形,理由如下:
∵,
∴,
∴,
∴四边形是平行四边形.·························································6分
【点睛】此题考查了平行四边形的判定、全等三角形的判定和性质等知识,熟练掌握相关判定和性质是解题的关键.
22.【答案】(1)补全频数分布直方图见解析
(2)92,
(3)A;A种语音识别输入软件的平均数较高,且A种语音的输入更稳定
【分析】(1)直接根据题意,补全表格,即可求解;
(2)根据中位数和众数的定义,即可求解;
(3)从平均数和方差的角度分析,即可求解.
【详解】(1)解:根据题意得:字数在60到70个之间的有1个,字数在70到80个之间的有4个,
补全频数分布直方图如图所示;
···························································2分
(2)解:根据题意得:用A种语音识别输入中92出现的次数最多,
∴A种语音识别输入的众数为92;···················