【初升高】河北邢台市第一中学2020中考提前自主招生数学模拟试?9?附解?- 百度文库 ر

[x22+2][3y+12+5]=10 x2=03y+1=0 x=2y=

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14ͼABCDУEFֱΪABBCе㣬CEDBDFGHEGGHHC= 546

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GH=2aHC=3a EG=a

EGGHHC=546 ʴΪ546

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15ֱ֪l1y=xa3ֱl2y=2x+5aཻڵAmnaΪmn0|1a|

= 1

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ֱl1y=xa3ֱl2y=2x+5aཻڵAmnɵómnĶԪһη̣̼ⷽɵómnֵٽmn0ɵóaȡֵΧɵóʽ|1a|𡿽⣺ã

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ãmn0 a2 |1a|ʴΪ1

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16ƽֱϵABΪA11B24MΪxϵһ㣬ҪʹMBMAֵMΪ 20 㡿D5ͼʣPAԳƩ·⣮

=a1a2=1

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𡿽⣺A11xĶԳƵA䣨11ֱABxڵM

ɶԳ֪MA=MA MBMA=MBMA=AB

NxMĵ㣬NA=NAʱNBNA=NBNA䣼AB=MBMA䣬 ԣMʹMBMAֵĵ㣬MBMAֵAB ֱABĽʽΪy=kx+b A䣨11B24ãã

ֱABĽʽΪy=x+2 ߵMΪֱABxĽ㣬 y=0ʱx+2=0 x=2

MΪ20 ʴΪ20

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17yxĺy=a2x222a1x+aaΪͼֻͬ㣬aȡֵΪ 20 㡿HAxĽ㣮

ֶκһκۼɣ 𡿽⣺Ƕκһκa2=0 a=2

a=0ʱΪy=2x2+xֻ㣬

a=20ʱyxĺy=a2x222a1x+aaΪͼֻͬ㣮 ʴΪ20

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