北师大版七年级第二章练习答案.pdf

1、12 12313 40534+700.53.45651670.55163B512345C14 150 0.2kg49.8kg50 0.2kg49.850.2kg mkg剟49.7kgA2O3.23.23.2C31 01ab 0a b+0ab0a b 0a b D40ac0b a+a b c 0ac0b a+2a=0b=2c=0b c+A2a=1b=0.9c=|bcB2a=0b=2c=0abc=Da b0ac0b a+0a 0c|abC15 C5mn0mn0nm|nm0nmmn C6|5|5|5=A|5|5|B|5|5=C|1.3|0DA71 4 12+=16 A22817 1425 4(0.2

2、5 1 0.5 0.75)99+=C2|1|2|3|4|1B3224=2(2)4=(2)2=|2|2 =222(2)(2)|2|2C4“+”18“”181806“”“”86675%8=D51a=1b=3c=(1 1)3 0+1 3 1 0+1 3 1 0+A1abc=Ba bc+b ca+D1a=1b=3c=(1 1)3 0+1 3 1 0+1 3 1 0+18 A1abc=BDa bc+b ca+0ba b c+a c b+b c a+3C6ababA|3ab+B|3ab+=C|3ab+D|3ab+E|3ab+=D7010.502+=B8|aa=a0|ab=ab|aaa19|abababab

3、abab0abA|aa=a0B|ab=abC|aaaD|abababB9|abab+=+|aba b+=+ababab00D1001nnnnA0 3 52+=2A1114223351234514232(2)3(3)36 =512345(1)(2)(3)(4)(5)120 =20 36120124b a=0a0b|3|ab=3ab=6a=2b=0a0b|3|ab=3ab=6a=2b=D0a0b|3|ab=3ab=3a=1b=CCDCD131A12212112A=3111 2A=4111(1)2A=512112A=61A=2016 3 672=2016A111421 77770.500.50.50

4、.570.5 1512Q20320201M(20 100)240+=2120(6 4)12+=)Q12 448=2048283(100 20 20)(6 4)50+=)(100 20 20)(6 4)70+=)50702022 122+3335+C2BC23AB BCCD=ABCDAD6BCx=23AB BCCD=3ABx=2CDx=11AD AB BC CDx=+=AD561111x=1x=3AB=2CD=BD26BD2D23 3ABC0DB45(2)5 2 7(C)=+=B5“”224;|2|2;(2)4;2=44122 2212|2|(2)2 2212|2|(2)2 24 1232 3

5、1+=B2337|11444+=+=A3xx8 x+8 3 5=83 61xx+=82(1)7xx+=5 6 7 7 3 8+=6 8 7 6 5P+=+4P=C25 4ab(1 25%)100a+=80a=(1 20%)100b=125b=200(80 125)5+=5C5A5(6)1+=B1.3(1.7)3+=C(11)7(11)(7)18=+=D(7)(8)(7)8 1=+=B6C11 15 73()m+=D73(4)(4 3)1+=48026 27 11(2)(3)(4)(99)(100)(101)=+50(101)=+51=D2m0|mm+m0|mm+0m0|mm+00m|0mm+0

6、m=|0mm+=0m|0mm+=B3ab5x 5+x+b=8+x+a a b=5 8+x x=3 A44564536514623 4 5 12S=+=28 C5abca b c+()A0 B2 C2 D22abcabc1a=1b=0c=1(1)00a b c+=+=A6AC90CD80DE60FE50FG70BG40A B90A C=80C D=60D E=50E F=70F G=40G B=+()()()()()()90 80 60 50 70 40210A CCDDEEFFGGBA B+=+=AB210A71200 2 100=100110029(1 0)(3 2)(5 4)(7 6)(9

7、 8)(199 198)+1 1 1 1 11=+100=C832491049 10 49 10 410 9 45315151515151515+=+=B9(1)927117111112121212123=+=(2)13()22+13 22=112=12=(3)5 17 3=25=(4)(32 18)(18 29)=+50 47=3=30(5)12 18 7 20=+30 27=3=(6)6(5)(12)+6 5 12=+1=(7)331431345(2)(1)()(51)(2)7 3447474477+=+=+=(8)9(4)(8)7+9 4 8 7=+13 8 7=+5 7=+12=(9)

8、20 137=+=(10)7 13 9=+3=(11)31 7 10 8 217 107=+=+=(12)11131(1)1(2)(3)(1)424244+355155424244=+15444=+154=10abcdeabcd2e1a=0b=0c=2d=1e=1 0 0 2 12a b c d e+=+=21120(15)20 1535=+=3512“”ABC2863 4 54 0 1537BCA+=+=+=+3 4 54 0 1537BCA+=+=+=+32 12 48B=12 102A=12 66C=28613abca b c|1a=|2b=|3c=1a=2b=3c=a b c 1a=2

9、b=3c=1a=2b=3c=2a b c+=020 141 2 3 4 5 6 7 895 96 97 98 99 100+(1 99)100(2 98)(3 97)(4 96)(5 95)(48 52)(49 51)50=+50=50154 3 9 7 92+=233 165 36 16 20+137Zed=B2(199 1)2 1 99+=4920299 2 101+=202 49 101 9999=+=(199 1)2 1 99+=4920299 2 101+=202 49 101 9999=+=B3(23 1)2 2 6 3 6 12 2 6 3 6 19+=+=23 19 4=)4B

10、434 11()(4)82=A51C35 15048 253141104050 494 3 2 1=48 474 3 2 1=50!48!50!50 494 3 2 150 49245048!48 474 3 2 1 =C0 xy xy|1x=|4y=1x=4y=0 xy 1x=4y=1x=4y=1x=4y=1(4)1 45xy=+=1x=4y=1 45xy=xy5BA B10 11 110A B=110 16 6=6EAa36 510095100950.860107abab0a=20a=20a 20b 220ab+=0a b=0a b+=0a b+=ab=1ab=0abab0a0b2|aba

11、b+=0c3|abcabc+=0c1|abcabc+=0c=2|abcabc+=C100 7 14.3=95 6.3 15.1CAB1CDD37 811|212aa1.52312a23(4)624=56()()165=2438 11111(3)()(3)32222=+=A34()143=B0(6)0 66=+=C11(3)(6)362=DC22(6)2 311=B3(5)(3)2+=5142()()6663+=13()(3)(3)93 =B4(1)(2018)2018 =0(1)0 1 1=+=(3)(3)9 =5(5)1=B39 516 C516 C510 5 1 6 10 5 6=10 3

12、0=10(30)=+20 C=C6161033 15 18(10F+=+=12(16=A CA C10 12=120=16 7(10=8+70(10=8+78=B7(1)(2019)2019 =0(1)1=40 111236+=11()122=2(3)6=132122 =3C810010%100(1 10%)+10%100(1 10%)(1 10%)99+=)A9100 100001W2W1900W=000)21000000(1000 5 500 10 20 200 40 100 1000 10)972W=+=000)972 000 900000 72000=7.2=41 1001007.2D

13、1012000 3.25%3 1170=)1170111111 22 399 100+11111122399100=+11100=99100=9910012“24”7 3(3)(7)24+=7 3(3)(7)24+=132.4km0.5km3 C42 2.4km9.4 C9.414(14)(3)11=5(22)17 =513()()1234+=(22)(9)13+=123()32154=1(10)(3)325=14225129+121015(1)6 6 0=+=28 12 16 233=+=3665(36)23940=433332110514(21 105 14)844444=+=+=513(

14、1)(48)64+131(48)(48)(48)64=+48 8 36=+76=(6)153121212234=+6 20 9=+43 5=(7)712510(31)(1)111311 13+795318143143=122=8532314|913|5719262619+5323149135719262619=+17 19=+2=44 1A3(2)3 21 =+=B2(3)9=C5 23+=D210533=D2abcdm2abcdm20a b+=1cd=|2m=|abmc dm+02 1m=+2 1 0=+1=A32216+=+=+45=+2=2 4=8 2=16=16=16=D4322 2

15、2 C510na1|10a nnan10n1n2052000002 10=A46 122()aa=33()aa=22aa=22()aa=33aa=33()aa=D23(2)32D323.46111.98346.13.4611002346.123.461100002346.1119800B410na1|10a nnan10n1n7400760004.0076 10=B510na1|10a nn47 an10n1n“48.1”94.81 10B61 12=C7*1()*323111()*3()228=C81m=0 xy+=1m=0 xy+=201820(1)1=+=148 1(5)(3)8+=3(

16、2)(8)8=51()()166+=13()(3)(3)93 =B2A328=AB8 816 =BC2416=CD5 23+=DC3ABCDA(16)(4)4=AB|2 5|3=BC2(3)9=CD3(2)8=DC49 40a b+=1cd=3m=9 3 1 7=+=D520172018(1)(1)+(1)1=+0=C65222222()333333m =C744444422222 22 2+=+5522=+52 2=62=A82212 3(3)2 22 9(3 2)=50 18 36=54=B9202101232(1101)1 20 21 21 213=+=B10A2.10.1)B2.050

17、.01)C2.05D2.050B115.2755.285aa5.285.2755.285aB1200.0204201351 619136.4 10(6 10)1.1 10131.1 101410na1|10a nnan1n1n88500000 60 5.1 10=)85.1 1015122.5952.605m xm2.56m2.62m12.60m2.6m2.6m0.1m2.60m0.01m2.60m2.5952.605m xm212.5952.605m xm2.56m2.62m162007200620062006222(2 1)2=2006200520052005222(2 1)2=1222(

18、2 1)2nnnn+=2007200620062006222(2 1)2=2006200520052005222(2 1)2=1222(2 1)2nnnn+=200720063222222=+20062005322(2 1)2222=+20052004322(2 1)2222=+222=+=6 17345452 3345454 4 4 4 441024 =31024 3 1021=(1021 1)4255=(255 3 1)4 191 =(191 3 1)4 143 =(143 3 1)4 107 =(107 3 1)480 =10211812a2b(ab)abab213234200920102 22222+20102009200820072222222+11100999999222(2 1)2=211112222212nnnnn=3234200920102 22222+20102009200820072222222=+53 200920082007222222=+20082222=+222=+6=