[]陕西省宝鸡市凤翔县竞存中学2019-2020学年七年级上学期第二次月考（12月）数学试题（图片版）

$$ 七年级数学参考答案第 1 页（共 3 页） 2019-2020 学年第一学期七年级数学教学质量检测（二） 参考答案及评分建议 一、选择题（共 10 小题，每小题 3 分，计 30 分．每小题只有一个选项是符合题意的） 1 2 3 4 5 6 7 8 9 10 B C B D C A D B D A 二、填空题（共 6 小题，每小题 3 分，计 18 分） 11．圆柱 12． 4 5 13．1 14．A 15．180 16．199 三、解答题（共 8 小题，计 72 分．解答应写出过程） 17．（每小题 4 分，满分 8 分） 解：（1）原式=1×3－8÷4 =3－2 =1． ····················································································· 4 分 （2）原式=(2x+3x)+(5－7) =5x－2． ··············································································· 4 分 18．（每小题 4 分，满分 8 分） 解：（1）移项，得 2x－5x=3+9， 合并同类项，得－3x=12， 解得，x=－4． ·············································································· 4 分 （2）两边同乘 12，得 2(5x－7)+12=3(3x－1)， 去括号，得 10x－14+12=9x－3， 移项，得 10x－9x =－3－12+14， 合并同类项，得 x=－1． ································································· 4 分 19．（本题满分 6 分） 解：原式=x 2 －2x 2 +4y+2x 2 －2y =(x 2 －2x 2 +2x 2 )+(4y－2y) =x 2 +2y， ······················································································ 3 分 当 x=－1， 1 2 y  时， 原式 2 1 ( 1) 2 2     =1+1 =2． ··························································································· 6 分 20．（本题满分 8 分） 解：（1）如图． ························································································· 2 分 （2）如图． ························································································· 4 分 七年级数学参考答案第 2 页（共 3 页） （3）4 3 3 2 ． ··················································································· 8 分 21．（本题满分 8 分） 解：（1）9 5． ························································································· 2 分 （2）如图（答案不唯一）； ··············································································· 5 分 （3）5 27．························································································ 8 分 22．（本题满分 10 分） 解：（1）5． ····························································································· 3 分 （2） 1 2 ． ····················