2023上海崇明区初三二模数学试题及答案

崇明区2022学年第二学期教学质量调研测试卷九年级数学评分标准（测试时间：100分钟，满分：150分）一、选择题（本大题共6题，每题4分，满分24分）．B2．A3．C4．D5．B6．C二、填空题（本大题共12题，每题4分，满分48分）．2；8．3；．1x3；．x2；1．m1；．增大；13．．；．135；31337．45；16．ab；；18．.32三、解答题（本大题共7题，满分78分）．（本题满分10121()2082221412(222………（841222225………（2．（本题满分10解：由②得xy0或x2y0（22xy，2xy，原方程组可化为或（2分+2xyx2yx，x，12··················································（2分+2解得原方程的解是y；y.12．（本题满分10分，第(1)小题5分，第(2)小题5解：（1）联结OC交ABH...........................................................(1OC过圆心，点C是的中点,AD=43HA=DH=23，OC1∴∠CHBCHA=90°九年级数学共6页第1页∴22AC2又∵21．∴3（1OAxOCxOHx3，⊥AB∴∠OHA=90°，xx22∴22AO2，∴··················································（17x，（1277∴，即：⊙O的半径长为222）过点D作⊥BC，垂足为MRt233（12133233sinB（123RtBDM中，BDsinB（12点C是的中点∴CDCA21（13∴DMCD27...........................................................................................(12114sinBCD22.（本题满分10分，每小题各5k0..........................................................(11）设所求函数解析式为＝＋b（20kb80，）............................................................(1由题意得：50kbk，b..................................................(2解得：y2x∴所求的yx的函数解析式为．..................................................(1210024002x12030..................................................(22）由题意得：x整理得，x2170x42000解得：1140,x230..................................................(1九年级数学共6页第2页经检验，1140,x230均为原方程的解，但当x1401y160，不符合题意舍去.........................................................(123012060..................................................(1∴x30∴答：所选购的甲、乙消毒剂的数量分别为30瓶、60．（本题满分12分，每小题各6证明：(1)∵四边形ABCD是平行四边形∥CD,ADBC................................................(2AGBGGFBG∴,................................................(2GMGDAGGDAGGF∴,................................................(1GMAGGMGF................................................(1∵∥∴AG2BAGBAGBCG................................................(1M∴∵∴BCG,MMGCCGF,∴FCG∽CMG................................................(1CGGF∴,GMCG∴CG2GMGF................................................(1AG2GMGF∴CGAG................................................(1∵四边形ABCD是平行四边形∴AEEC∴ACBD................................................(1∴平行四边形ABCD是菱形................................................(1．（本题满分12分，每小题各4解：（1）由题意得A（50）（，5................................................(1把A5，）B05）代入yx2bxc255b0b6解得：................................................(2c5yx∴c526x5D（，-4）................................................(12M作y轴的平行线交直线ABH九年级数学共6页第3页7M(a,-)yx6x52把47a26a5439a,a解得：12227M(a,-)在抛物线对称轴左侧的图像上4337∴a，M(,-)................................................(123247237H(,)................................................(1xyx5y把∴∴222................................................(14M落在△74214m∴................................................(1P(x,xQ(x,x6x23由题意可得∥，∵．∴四边形PEDQ为平行四边形或等腰梯形．PE∥DQ时，四边形PQDE为平行四边形，此时P在对称轴左侧，则=DEE2)，ED6由题意x5x26x5x5x................................................(12∴x25x6xx3舍）解得：12∴Q(2,................................................(1与DQ不平行时，四边形为等腰梯形，此时P在对称轴右侧，PQPE=DQ∴∠AED=∠QDE由题意可得：∠OBA=AED=QDE=45°；作QN⊥DE,垂足为N，可得△QND是等腰直角三角形，九年级数学共6页第4页6x则x3；Nx2x3x26x5(.............................................(1分)xx3舍）解得：12∴Q(4,................................................(1．（本题满分14分，第(1)小题4分，第(2)小题5分，第(3)小题5C90ACFBDC90................................................(11）∵CFBEC90∴∵∴∴∴C90DBCACFBDC90................................................(1DBC................................................(1BCCDBC23∴tanACFtanDBC................................................(1F作FH⊥AC,垂足为H................................................(1AHFACB90∴∴AFAHFHAH∴;BFCHBCAC∵BCAC6∴AH2FH................................................(1AF2FH∴BFCHtanACFtanDBCFHCDx................................................(1CHBCAF2FH323∴yx（0x6................................................(2BFCH(3)∵DCGACB90∴△DGC与△相似有两种情况................................................(1GA时①当ADFCDG∴FAD∽CGD九年级数学共6页第5页DCGACFAFD90∴∵DBC,EDCCDB∴ECD∽CDBCDBD∴∴CD2DEBDEDCDFDDEBD2同理：∴CDFDxBCFD3x353∵sinA∴∴x................................................(1ABAD356x22AF∴yx5151................................................(13BFGABC时CDGG90CDGADF②当AABC90∵∴A∴AFFDF作FHAC,垂足为H6x