[]江苏省徐州市部分学校2018届九年级下学期期中（一模）考试数学试题（答案pdf版）

九年级数学期中试题参考答案 ( 第 1 页 共 5 页 ) 2017-2018学年度第二学期徐州市区联校期中检测 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 A B D C B D D C 9. 5 10. 115º 11. 1.2×104 12. 13. k ≤ 4 14. 120º 15.6π 16.14 17. 75º 18. 6n－1 19. (1) 原式= 1-2-2 + 1······················································································4分 =-2································································································ 5分 (2) 原式= 2 1 1( ) 1 1 ( 1) x x x x x       ·······································································7分 = 2( 1) 1 x x x x    ·················································································· 9分 = x+1····························································································10分 20. (1) 解法一：(配方法) ：x2+ 2x－2= 0； x2+ 2x+1=3.······························································································1分 (x + 1)2=3.································································································ 2分 x + 1= 3 .······························································································ 3分 x1=－1 3 ，x2=－1 3 .············································································5分 解法二：(公式法) a=1，b=2，c=－2. ····················································································2分 △=b2－4ac = 4+8=12.·················································································3分 1 2 12 1 3 2 x     ， 2 2 12 1 3 2 x      (结果正确没化简，扣 1分) .·········· 5分 (2) x－2 x+2＞0，························································································ 7分 －x>－2.·····························································································9分 x<2. ································································································10分 x y 6 九年级数学期中试题参考答案 ( 第 2 页 共 5 页 ) 21. 如图 (列表或树状图 ).···············································································6分 共有 9种等可能情况，满足条件的有 3种. 所以 P(相同颜色的球)= 1 3 .·················