四川省锦江区2021-2022学年中考数学适应性模拟试题含解析及点睛

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17ூ᪆௃(1)᪷ᱥḄḄឋAḄᙶ᪗᪷ᦪ!ᱥḄ᪆"#(2)ᐜ᪷%&ᳮCE,(ᑖ*+,-./NQPC=90஺1#/NPQC=90஺1#234PCQ678981tḄ:#(3)᪷ᦪ!7ACḄ᪆"᪷SAACQ=SAAFQ+SACPQSAACQ=LFQAD=-■!■(t-2)2+l,24;<ᓽ>.ூ@௃.(1)•ᱥḄ6x=l,OCDEḄ9B⚔ᑖDEC(3,0),D(3,4),E(0,4),AᙠDEG...Aᙶ᪗6(1,4),HᱥḄ᪆"6y=a(x-1)2+4,IC(3,0)JᐭᱥḄ᪆"a(3-1)2+4=0,a=-l.ᦑᱥḄ᪆"6y=-(x-1)2+4,ᓽ=-X2+2X+3y(2);⚪Pᨵ.OC=3,OE=4,•CE=y]0C2+0E2=V32+42=5/NQPC=90஺1PCOCVcosZQPC=R3-t3»15.•.R=St=1r/NPQC=90஺1CQPCVcosZQCP=CPCEt=3—t513159.,•/t=1ᡈt=A1PCQ67898;(3)VA(1,4),C(3,0),H7ACḄ᪆"6y=kx+b,ᑣᨵ:k+b=4k=-2,Y,,ᦑ7ACḄ᪆"6y=-2x+2.3k+b=0b=6VP(L4-t),Zy=4-tJᐭy=-2x+2[\=1+],ttt2QḄ^ᙶ᪗61+]Zx=l+^Jᐭy=-(x-1)2+4[_=4-1

18.••QḄ`ᙶ᪗64-422AQF=(4-—)-(4-t)=t--,44SAACQ=SAAFQ+SACFQ11=-FQAG+-FQDG,22=-FQ(AG+DG),2=—x2(t-—),24=——(t-2)2+l,4.•./t=21AACQḄ☢bᨬᜧᨬᜧ:E1.ூe௃ὃghijkᦪlᔠ⚪noḄpqᨵ.ᱥḄḄឋᦪ!>ᱥḄ᪆"ᦪ!>7Ḅ᪆"%&ᳮ┦898kᦪ98☢bijkᦪḄᨬ:stuvwoᑖxuvḄyᵨ.24ஹ(1)@|᪆(2)-4ூ᪆௃H*I}~Ḅ┝ᑖD6AஹB,I*┝ᡭḄᓇᑖD6“ஹb,ᐸ*IᓇᑖD6ஹ஻᪷⚪Pw᪛(᪷ᭆ᳛">ᓽ.ூ@௃(1)H*I}~Ḅ┝ᑖD6AஹB,I*┝ᡭḄᓇᑖD6“ஹb,ᐸ*IᓇᑖD6஻zஹn,᪷⚪Pw᝞᪛.ᵫGpGᐳᨵ8+#(2)ᵫ(1)pPIᓇPI┝ᐳᨵ8+Ḅjᡭ┝Ḅᨵ2+ᡠᨵḄឋ¡.

1921.--P(jᡭ┝)84ூe௃ITI᝞B©ªᨵn+¬®©ªḄឋ¡~ᐸ[©ªA¯m+±²©ªAḄᭆ᳛P(A)=—.n25ஹ(1)(4,0)#(2)-lCḄᙶ᪗᪷¹º஺4BC6BḄᙶ᪗»¬>Aᓽ#(2)ᐜ>ᱥ¼xḄ*B½ᔠ¼ᓽ.ூ@௃2Q.(1)/x=01kᦪy=Y¿2Ḅ:62,.•.CḄᙶ᪗6(0,-2)•.•¹º஺ÀC6:.OA=CB,AB=CO=22Qst_x~—Â2=—2,᳝=0,x,=4.55'.•.3Ḅᙶ᪗6(4,-2)..••AḄᙶ᪗6(4,0).2g(2)stiYÈߟ2=0,᳝=-1,%2=5.ᵫ¼p/y<01xḄ:ÌE1<%<5.ூe௃Í⚪ὃghijkᦪÎÏÐ⚪woijkᦪ}"Ð⚪⚪ḄᐵÒEᮣÔyᵨÎÏpqÕÖ៉ijkᦪḄ¼ឋ.26ஹ(1)Ù»AÚÛÜ75Þ8ÚÛÜ25Þ#(2)/ᖪàÙ»AÚÛÜ25Þ1ᖪàáᑭᨬᜧ<1áᑭ61875ᐗ.ூ᪆௃⚪ᑖ᪆.(1)HᖪàäÙ»AÚÛÜxÞᯠæ᪷ᐵ.ᖪà⚜è»éê63500ᐗᑡstìÐ⚪#(2)Hᖪà├îïᢇÛÜáᑭyᐗᯠæ>yxḄkᦪᐵ"ᯠæ᪷jkᦪḄឋñòóôḄ:Ìõáᑭᨬö1Ḅsᫀ.⚪᪆..(1)HᖪàäÙ»AÚÛÜxÞᑣBÚÛÜ6(100-x)Þ

20᪷⚪P30x+50(100-x)=3500,x=75,ᡠw100-75=25,ø.äÙ»AÚÛÜ75ÞBÚÛÜ25Þ#(2)Hᖪà├îïᢇÛÜáᑭyᐗùúIy=(45-30)x+(70-50)(100-x),=15x+2000-20x,=-Sx+2000,•••BÚÛÜḄ»éᦪô}ûüAÚÛÜᦪôḄ3ý100-x<3x,•*.x>25,Vk=-5<0,.♦.x=251yᨬᜧ:6-5x25+2000=1875(ᐗ)ø.ᖪàÙ»AÚÛÜ25ÞBÚÛÜ75Þ├îïᢇÛÜ1áᑭᨬö<1ᑭþ61875ᐗ.ὃ.1.ᐗjstḄäᵨ#2,jkᦪḄäᵨ.27ஹ(1)ÿ
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