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(3)(7,42)1.4:mn,2x5yn-2(m+5)x|m-n+4|y,m+n-37.MNx,MN63,M-N26.m,x(-x)m+1(-x)2m-2(-x)3m+1=xx+1x6m-1x=-1,0,1.AMDNABCDEF,AB=DE,AC=DF,AM=DN.BAC=40,ABC=35,DFE=105.,().(A)0(B)12(C)3(D)42.1,ABCD1,1ACMN,MBN=135.MN().(A)1+2(B)2+2(C)3+2(D)223.abc1a+b1a+c+14(b-c)2=0.ab+ac().(A)-2(B)-1(C)1(D)224.2,ABC,BAC=60,BC=18,DAB,AC=BD,ECD.AE().(A)12(B)9(C)93(D)5.abcd2005a3=2006b3=2007c3=2008d3,32005a2+2006b2+2007c2+2008d2=32005+32006+32007+32008.a-1+b-1+c-1+d-1().(A)1(B)0(C)-1(D)16.xOy,y=2kx+3-4kxyAB,PAB,PMxM,PNyN.OMPN().(A)3(B)4(C)6(D)8(7,28)31.3,ADABC,C=2B,AB=a2-4b+4,AC=8c-27-2b2,CD=9+4a-c2.BC=.2.abca-b+c=7,ab+bc+b+c2+16=0.(a-1-b-1)abc(a+b+c)a+b+c.9200713.4,ABCDACBDO,EFGABOCOD,OA=AD,OB=BC,CD=3AB.FEG.44.5ABCD,ABx,E(2,6),F(3,4).OFE,,5.:,.ABP,EP,P.(20)MNP,6(a)(b)(c),S1cm2S2cm2S3cm2,h1cmh2cmh3cm,V1cm3V2cm3V3cm3(V1V2V3).MNP(PNMNPMPMNMPNNMPMNP),MNP.66,,.h(cm)t(s)789.789(1)7896?(2)h1h2h3S1S2S3;(3)V3=9m2+4m+41125cm3,n2+6n+45n+3cm3/s,mn,MPN.(25)10,l1l26,l1l21Ol2A,Pl110.POPBPC,BC,l2MN.AMAN?,;,.(25)k,x(k2-2k)x2+(4-6k)x+8=0.k.011.D.(1)m=-5,n2,2x5yn-202x5yn-2.,m+n-3,.(2)M=x6+1,N=x3+1,M-N2=-2x3.-2x3,.(3)m=0,x=0(-x)2m-2x6m-1,,x=0,.(4)DNDEF(11).11RtAMCRtDNF.,DFE=ACM=BAC+ABC=75..2.B.AM=x.ABMCNB.,ABCN=AMCB,1CN=x1,CN=1x.MN=AM+AC+CN=x+2+1x=x-1x2+2+22+2.3.A.4(ab+1)(ac+1)+(ab-ac)2=0,(ab+ac)2+4(ab+ac)+4=0,[(ab+ac)+2]2=0.ab+ac=-2.124.B.12,ACF,CF=AD.BF,CCGABBFG,DGAG.AC=DB,CF=AD,,AC+CF=DB+AD,AF=AB.BAC=60,,ABF.AF=BF,F=60.CGAB,,CFG.CF=FG=CG.AGFBCF,AG=BC=18.CGAD,ACGD.,CDAG,EAG.AE=12AG=1218=9.5.D.x=1a+1b+1c+1d,2005a3=2006b3=2007c3=2008d3=k3.,abcdk,2005a2=k3a,2006b2=k3b,2007c2=k3c,2008d2=k3d;2005=k3a3,2006=k3b3,2007=k3c3,2008=k3d3.3k3a+k3b+k3c+k3d=3k3a3+3k3b3+3k3c3+3k3d3,31a+1b+1c+1d=1a+1b+1c+1d.,3x=x.,x=0,x=-1,x=1.abcd,x0.x=a-1+b-1+c-1+d-1=1.6.C.P(x0,y0),OMPNS.x00,y00,S=x0y0.P(x0,y0)y=2kx+3-4k,,y0=2kx0+3-4k.S=x0(2kx0+3-4k)=2kx20+(3-4k)x0.,S=42k0-(3-4k)242k,16k2-(24-8S)k+9=0.k,=[-(24-8S)]2-41690.|24-8S|24.S6S0().S=6,k=-34.11200711.73.ACE,CE=CD,DE.E=CDE=12ACD=B.ADBAC,BAD=EAD,ABBD=ACCD.,ABDAED.AB=AE=AC+CE=AC+CD.AB=a2-4b+4,AC=8c-27-2b2,CD=9+4a-c2,a2-4b+4=(8c-27-2b2)+(9+4a-c2),(a-2)2+2(b-1)2+(c-4)2=0.,a=2,b=1,c=4.,AB=4,AC=3,CD=1.BD=43,,BC=BD+CD=43+1=73.2.-1.(-b)+(a+c+1)=8.(a+c+1)(-b)=c2+16.,a+c+1-bx2-8x+c2+16=0.,=(-8)2-4(c2+16)0.,c20.c=0.x1=x2=4,a+c+1=4,-b=4,a=3,b=-4.(a-1-b-1)abc(a+b+c)a+b+c=(3-1+4-1)0[3+(-4)+0]3-4+0=-1.3.120.13,AGBFFG,EEPFGP.13AB=2a,CD=3AB=23a.OA=AD,GOD,,AGOD.,AGB=90.,AFB=90.,ABFG,ABE.FGOCOD,,FG=12CD=3a=2asin12FEG.12FEG=60,FEG=120.4.53,0.14,OE,FFPOEAB14P,EPOFG.OEPF,SOEF=SOEP.SOEF-SOEG=SOEP-SOEG,SEFG=SOGP.,EP,P.OEy=3x.OEPF,,PFy=3x+b.F(3,4),4=33+b,b=-5.,PFy=3x-5.y=0,3x-5=0,x=53.,P53,0.(1)7MNP60s,8MNP54s,,860-54=6(s).,960-24=36(s).,60-6-36=18(s).,V1V2V3,,MNP36s18s6s.,789NPMPMNMNP.(2)Vcm3/s.789(1)21h1+h3=24,h2+h1=30,h2+h3=18;V1+V2+V3=60V,V2+V1=54V,V3+V2=24V.h1=18,h2=12,h3=6;V1=36V,V2=18V,V3=6V.,S1=V1h1=36V18=2V,S2=V2h2=18V12=32V,S3=V3h3=6V6=V.S1S2S3=2V32VV=432.(3)m2+4m+41125=(m+2)2+01125,,m=-2,m2+4m+4112501125.,V372.V=n2+6n+45n+3,n2+(6-V)n+(45-3V)=0,=(6-V)2-41(45-3V)0.,V12V-12().n=3,V12.(2),V3=6V.V372,6V72,V3=6V=72.,m=-2,n=3.,V=12.V1+V2+V3=60V=6012=720(cm3).,720cm3.15,PPDl2D,15OAOBOCOMONOP.PD=6,OA=OB=OC=1.AM=m,AN=n,PC=p,DN=x,DM=m+n-x.,OPMN,,BM=AM=m,CN=AN=n,PB=PC=p;OAMN,OBPM,OCPN.SPMN=SOMN+SONP+SOPM=12MNOA+12PNOC+12PMOB=12(MN+PN+PM)=m+n+p,SPMN=12MNPD=3(m+n),m+n+p=3(m+n).p=2m+2n.RtPDNRtPDM,PD2+DN2=PN2,PD2+MD2=PM2,62+x2=(p+n)2,62+(m+n-x)2=(m+p)2.-(m+n)(2x-m-n)=(n-m)(m+n+2p)=5(n-m)(m+n),x=3n-2m.36+(3n-2m)2=(2m+3n)2,36=24mn.,mn=115,AMAN=115.,AMAN,115.k=0,4x+8=0,x=-2.k=0,.k=2,-8x+8=0,x=1.k=2,.k02,(kx-2)[(k-2)x-4]=0.x1=2k,x2=4k-2.x1=2k,k=2x1.k=2x1x2=4k-2,x1x2+2x1-x2=0.(x1-1)(x2+2)=-2=1(-2)=2(-1).x1x2,,x1-1x2+2.,x1-1=1,x2+2=-2x1-1=-2,x2+2=1x1-1=2,x2+2=-1x1-1=-1,x2+2=2.x1=2,x2=-4x1=-1,x2=-1x1=3,x2=-3x1=0,x2=0().k=1,-2,23.,k-2,0,1,223.(,438000)3120071