2021-2022学年贵州省黔南州八年级（下）期末数学试卷（附答案详解）

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2021-2022
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•._10ᡝ<ᙳbᜩḄᵨᵯe8.4f.g12⚓ᐳ16⚓

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1322.ூ1ᫀ௃5(1)•••48=13,BC=5,ACLBC,AC=7AB2-BC2=V132-52=12,(2)vAC=12,CD=15,AD=9,•••CD2=AC2+AD2,

•/DC;ÚCRC9•••789ABCDḄ☢Ü=^BC-AC+^AD.AC=3x5x12+[x9x12=84.ூ᪆௃(1)᪷ᳮsACᓽ"^(2)ᑭᵨᳮḄ⌮ᳮsG4DC;ÚCRC9¿O1ᓽ".%⚪ὃ'ᳮHᳮḄ⌮ᳮᐵ\;᪷ᳮsAC1.23.ூ1ᫀ௃:প஺=79+81+82+85+83)=82(ᑖ)X=g(88+79+90+81+72)=82(ᑖ)S'=|[(79-82)2+(81-82)2ᓺ-82)2+(85-82)2+(83-82)2]=4+S/=|[(88-82)2+(79-82á+(_)2+(81-82)2+(72-82)2]=42,9082(2)⌱çᵬé~êëìᔠ〉ÕᵬḄïðoᡂòêðó.ூ᪆௃(1)᪷<ᙳᦪḄmHïᑖ@¿=mᓽ"^(2)᪷ïḄ}ïôoᦪôóᓽ"s1ᫀ.⚪ὃ'ïḄ}:õᙢ஻{ᦪ,X1X2,…XnḄ<ᙳᦪ3ᑣïS2=^[(%-x)2+(x-x)2+-+(x-x)2],øù᧜(ûᦪḄüýᜧoïôᜧüýឋô2nᜧùÿᡂ.24.ூᫀ௃(1)4cBḄᑖ:.z.1=Z.2,•MN//BC,:.z.1=Z.3,
•
z2=z3,•OE—OC,ᳮOC=OF,:.OE=OF(2)஺ᙠACᑮAC!"#AEC$%#.ᳮᵫ஺'ACḄ!40=CO,•••E0=F0,(14⚓ᐳ16⚓

14"#AEC$+"#•••CEᑖ4CB,C$ᑖN4CG,ECF=+-CG=+NACG)=90°,•••+"#AECF%#.(3)/0.ᳮᵫ᝞2᝞345BF,•••CEᑖ4CB,C$ᑖN4CG,ECF=*CB+2CG=+^ACG)=90஺,7"#BCEE8#ᑣBFLEC,:ᙠADFC/0;ᙠ<=>'90஺ᡠ@/;ᙠᐸ'8#.ூ᪆௃(1)ᵫCMN஻BC,MNDNBC4ḄᑖEE,DZBC4Ḅ᜜>ᑖEF,᧕HOE=OC,ᳮOC=OF,ᑣHOE=OF=OC(2)᪷J+"#ḄᑨL@M%#ḄᑨLHNᓽ.(3)8#ḄᑨLP⚪7R8#ᑣSᨵ"ᩩVWX>YVᚖC[\ᑖ᪆]Nᓽ.^⚪ὃ`a+Ḅឋc>ᑖḄLdWῪf>#ḄᑨLgh#ஹ8#ḄᑨLjk〉mnopᦪ#rᔠtuḄvᵨ.25.ூᫀ௃(1)ᵫy=-3x+3,xy=0,Hy3%+3=0,AX=1,(2)zC"Ḅ᪆⊤}~'y=kx+b,of4fc+h=0ᵫ3x=4,y=0%=3,y=—aᐭ⊤}~y=k%+bH஽+ᓃ=_f,H:U=-6.••CḄ᪆⊤}~'y=|x-6y=-3%+3(3)ᵫy=|x—6x=2Hy=-3
•
஺(2,-3),•AD=3,

1519SுADC=yX3x|-3|=(4)

•ADP^j/^40cA஺ADPḄ☢44DC☢Ḅ2
•.ADCCᑮCA஺ḄḄ2ᓽCᙶ᪗ḄX=6,ᑣPᑮAD=6,
•
Pᙶ᪗±6,vy=1.5x—6,y=6,:.1.5x—6=6,Hx=8.•••Pi(8,6).,,,y=1.5x—6,y=—6,:.1.5x—6=—6,H=0,“2(0-6)ᡠPḄᙶ᪗'(8,6)ᡈ(0,-6).ூ᪆௃(1)LḄ᪆~xy=0]NxḄᓽ(2)zḄ᪆~'y=kx+b,ᵫ3ὶh¢£]NhbḄ(3)ὶh¢£]NDCḄᙶ᪗¤\]NS-DC(4)AADP«¬ADC40,᪷JZMOPḄ☢AADC☢Ḅ2HPḄᙶ᪗.^⚪ὃ`Ḅy®ᦪḄឋcf>#☢Ḅ¯°Wᨵᐵ²ᑭᵨ3Ḅᙶ᪗HN᪆~⚪ᐵ´.(16⚓ᐳ16⚓