2023人教版八年级数学寒假作业答案

时间匆匆，又一个寒假在同学们的期盼中降临，在寒假中不只是玩耍，还有寒假作业需要完成，关于寒假作业的答案你参考了吗?下面小编为大家收集整理了“2023人教版八年级数学寒假作业答参考”，欢迎阅读与借鉴!wKr本库

wKr本库

八年级数学寒假作业答案1wKr本库

第1页—第3页wKr本库

1.选择题wKr本库

1A 2D 3A 4CwKr本库

2.填空wKr本库

(1)T=20-6h20,6ThhwKr本库

(2)Q=6x105-pt6x105pQt0≤t≤6x105/pwKr本库

(3)S=1.5b(4)0≤x≤70≤y≤550wKr本库

3.解答题wKr本库

(1)y=Q/a-x–Q/a(0≤x≤a)wKr本库

(2)y=80-2xwKr本库

20wKr本库

(3)①-2≤x≤3wKr本库

②当x=3,y有最小值为1/2wKr本库

③当-2≤x≤0，y随x的增大而增大，当0≤x≤3，y随x的增大而减小wKr本库

(4)①`v=800-50twKr本库

②0≤t≤16wKr本库

③当t=8时，v=800-50x8=400wKr本库

④当v=100时，100=800-50twKr本库

T=14wKr本库

第5页—第7页wKr本库

选择题wKr本库

1B 2C 3C 4B 5B 6A 7B 8DwKr本库

填空wKr本库

(1)1(2)y=2x+1-1(3)m<2n<3(4)y=-3x+3wKr本库

(5)y=x+3(6)y=64x+48(7)S=2n+1(8)y=1/5x-630wKr本库

解答题wKr本库

(1)设y=kx+bwKr本库

-4k+b=15wKr本库

6k+b=-5wKr本库

k=-2b=7wKr本库

y=-2x+7wKr本库

(2)略wKr本库

(3)①表示y与x的关系，x为自变量wKr本库

②10时离家10km13时离家30kmwKr本库

③12时-13时，离家30kmwKr本库

④13kmwKr本库

⑤2时-13时wKr本库

⑥15km/hwKr本库

八年级数学寒假作业答案2wKr本库

第9页—第11页wKr本库

1.选择题wKr本库

(1)A(2)C(3)CwKr本库

2.填空wKr本库

(1)y=-2x(2)m<2(3)y=5x+3(4)y2>y1(5)y=-2x+10025wKr本库

(6)9wKr本库

3.解答题wKr本库

(1)①Q=200+20t②(0≤t≤30)wKr本库

(2)①y=80(0≤x≤50)wKr本库

y=1.9x-15(50≤x≤100)wKr本库

②y=1.6xwKr本库

③选择方式一wKr本库

(3)①在同一直线上y=25/72xwKr本库

②当x=72时，y=25wKr本库

当x=144时，y=50wKr本库

当x=216时，y=75wKr本库

y=25/72x(0≤x≤345.6)wKr本库

③当x=158.4时，y=25/72x158.4=55wKr本库

(4)①y甲=2x+180wKr本库

y乙=2.5x+140wKr本库

②当x=100时，y甲=200+180=380wKr本库

Y乙=140+250=390wKr本库

380〈390wKr本库

租甲车更活算wKr本库

第13页—第15页wKr本库

1.选择题wKr本库

(1)D(2)C(3)CwKr本库

2.填空wKr本库

(1)x=2wKr本库

y=3wKr本库

(2)x=2x>2wKr本库

(3)-3-2x=-5/8y=-1/8wKr本库

(4)1/20x=2wKr本库

y=3wKr本库

(5)y=5/4xwKr本库

2.解答题wKr本库

3.(1)略wKr本库

(2)①依题意wKr本库

-k+b=-5wKr本库

2k+b=1wKr本库

解得wKr本库

k=2b=-3wKr本库

y=2x+3wKr本库

当y≥0时wKr本库

2x-3≥0,x≥3/2wKr本库

②当x<2时，2x<4wKr本库

则2x-3<1wKr本库

即y<1wKr本库

(3)①y会员卡=0.35+15wKr本库

y租书卡=0.5xwKr本库

②若y会员卡〈y租书卡wKr本库

则0.35x+15<0.5xwKr本库

x>100wKr本库

租书超过100天，会员卡比租书卡更合算wKr本库

(4)设A(m,n)wKr本库

1/2x4xm=6wKr本库

m=3wKr本库

n=2wKr本库

A(-3,-2)wKr本库

y=2/3x,y=-2/3x-4wKr本库

(5)①y甲=0.8x1.5X+900=1.2x+900(x≥500)wKr本库

Y乙=1.5x+900x0.6=1.5x+540(x≥500)wKr本库

②若y甲=y乙wKr本库

1.2x+900=1.5x+540wKr本库

x=1200wKr本库

当x<1200时，选择乙厂wKr本库

当x=1200时，两厂收费一样wKr本库

当x〉1200时，选择甲厂wKr本库

2000>1200,选择甲厂wKr本库

y甲=1.2x2000+900=3300wKr本库

八年级数学寒假作业答案3wKr本库

第17页—第19页wKr本库

1.选择题wKr本库

(1)C(2)D(3)CwKr本库

2.填空wKr本库

(1)630(2)0.170.17(3)35(4)①238.1824②12.9③2万wKr本库

3解答题wKr本库

(1)wKr本库

①七大洲亚洲wKr本库

②亚洲和非洲wKr本库

③100%wKr本库

④大洋洲wKr本库

⑤不能wKr本库

(2)①一车间第四季度wKr本库

②一车间二车间wKr本库

③①是图(1)得出的②是图(2)得出的wKr本库

(3)①48②0.25③哪一个分数段的学生最多?70.5~80.5的学生最多。wKr本库

第21页—第23页wKr本库

1.选择题wKr本库

(1)B(2)B(3)C(4)BwKr本库

2.填空wKr本库

(1)20%30%25%25%(2)扁形36%115.2度(3)411wKr本库

3解答题wKr本库

(1)wKr本库

县ABCDEFwKr本库

人口(万)9015722737771wKr本库

百分比12.9%2.1%10.3%39.1%11.0%24.5%wKr本库

圆心角度数46.47.737.1140.839.788.2wKr本库

(2)图略wKr本库

(3)身高(cm)频数wKr本库

154.5~159.52wKr本库

159.5~164.54wKr本库

164.5~169.56wKr本库

169.5~174.510wKr本库

174.5~179.55wKr本库

179.5~184.53wKr本库

(4)图略结论：只有少数人对自己工作不满。wKr本库

(5)①200.16②略wKr本库

第25页—第27页wKr本库

1.选择题wKr本库

(1)B(2)C(3)A(4)C(5)B(6)CwKr本库

2.填空wKr本库

(1)∠D∠CDCODOC(2)DECDE∠D600wKr本库

(3)∠CADCD(4)50010108(5)ADECAEwKr本库

3解答题wKr本库

(1)①△DCE可以看作是△ABF平移旋转得到的wKr本库

②AF不一定与DE平行,因为∠AFE不一定等于∠DwKr本库

(2)∠ABC=1800x5/18=500wKr本库

∠C=1800x3/18=300wKr本库

∠B’CB=∠A+∠ABC=800wKr本库

∵△ABC≌△A’B’C’wKr本库

∴∠A’=∠A=300wKr本库

∠B’=∠ABC=500wKr本库

∠B’BC=1800-∠B’-∠B’CB=500wKr本库

(3)①略②分别取各边中点,两两连接即可.wKr本库

(4)延长AD至E,使AD=DE,连接BEwKr本库

∴AD=EDwKr本库

∵D为BC的中点wKr本库

在△BDE和△CDA中wKr本库

BD=CD∠ADC=∠BDEDE=DAwKr本库

∴△BDE≌△CDAwKr本库

∴BE=ACwKr本库

AEwKr本库

∴ADwKr本库

八年级数学寒假作业答案4wKr本库

第29页—第31页wKr本库

选择题wKr本库

(1)D(2)B(3)B(4)CwKr本库

2.填空wKr本库

(1)6(2)200(3)BO=CO(4)AB=DC∠ACB=∠DBCwKr本库

3.解答题wKr本库

(1)∵AE=CFwKr本库

∴AE+EF=CF+EFwKr本库

∴AF=CEwKr本库

∵CD=ABDE=BFCE=AFwKr本库

∴△CDE≌△ABFwKr本库

∴∠DEC=∠AFBwKr本库

∴DE‖BFwKr本库

(2)△ABE≌△ACGwKr本库

△ABD≌△ACFwKr本库

∵AB=ACwKr本库

∴∠ABC=∠ACBwKr本库

∵BD平分∠ABC，CF平分∠ACBwKr本库

∴∠ABD=∠ACFwKr本库

∵∠BAF=∠BAFwKr本库

AB=ACwKr本库

∴△ABD≌△ACFwKr本库

(3)BA=BCwKr本库

∵AB=BCwKr本库

∠B=∠BwKr本库

BE=BDwKr本库

∴△BEA≌△BDCwKr本库

(4)wKr本库

证明∵EH=FHDH=DHDE=DFwKr本库

∴△DEH≌△DFHwKr本库

∴∠DEH=∠DFHwKr本库

(5)①证明∵∠BCA=∠ECDwKr本库

∴∠BCA-∠ACE=∠ECD-∠ACEwKr本库

即∠BCE=∠ACDwKr本库

∵EC=DCBC=ADwKr本库

∴△BEC≌△ADCwKr本库

∴BE=ADwKr本库

②BE=AD仍然成立wKr本库

证法同(1)wKr本库

第33-35页wKr本库

1.选择题wKr本库

(1)A(2)D(3)D(4)DwKr本库

2.填空题wKr本库

(1)EP=PF(2)角平分线角平分线上的点到两边距离相等。wKr本库

(3)7cm(4)500wKr本库

3.解答题wKr本库

(1)证明：作DE⊥ABwKr本库

∵AD平分∠CADwKr本库

DE⊥ABDC⊥ACwKr本库

∴DC=DEwKr本库

∵∠C=900AC=BCwKr本库

∴∠B=450wKr本库

∵DE⊥ABwKr本库

∴∠B=∠EDB=450wKr本库

∴BE=DEwKr本库

∵∠C=∠AED∠CAD=∠DAEAD=ADwKr本库

∴△ACD≌△AEDwKr本库

∴AC=AEwKr本库

∴AB=AE+BE=AC+CDwKr本库

(2)∵OD平分AOBwKr本库

∴∠1=∠2wKr本库

∵OB=OAwKr本库

∠1=∠2wKr本库

OD=ODwKr本库

∴△OBD≌△OAD(SAS)wKr本库

∴∠3=∠4wKr本库

∴OD平分∠ADBwKr本库

∵PM⊥BD，PN⊥ADwKr本库

∴PM=PNwKr本库

(3)∠BED=∠CFDwKr本库

∠BDE=∠FDCwKr本库

BD=CDwKr本库

∴△BED≌△CFD(AAS)wKr本库

∴DE=DFwKr本库

∵DE⊥AB，DF⊥ACwKr本库

∴AD平分∠BACwKr本库

(4)证明：作MN⊥ADwKr本库

∵DM平分∠ADCwKr本库

CM⊥CDNM⊥ADwKr本库

∴MC=NMwKr本库

∵M为BC的中点wKr本库

∴BM=CMwKr本库

∵NM⊥AD，BM⊥ABwKr本库

∴证明∵DE平分BC，DE⊥BCwKr本库

∴CM=BMwKr本库

∵NM⊥AD，BM⊥ABwKr本库

∴AM平分∠DABwKr本库

(5)∵DE平分BC，DE⊥BCwKr本库

∴BE=CEwKr本库

∵AE平分∠BACwKr本库

∴EF=EGwKr本库

∵BE=CEEF=EGwKr本库

∴△BFE≌△CGEwKr本库

∴BF=CGwKr本库

第37~39页wKr本库

1.选择题wKr本库

(1)D(2)D(3)D(4)D(5)B(6)BwKr本库

2.填空题wKr本库

(1)完全重合对称轴另一个图形对称轴对应wKr本库

(2)2角平分线(3)700wKr本库

(4)ABCDEHIKMOTUVWXYwKr本库

3.解答题wKr本库

(1)(2)(3)(4)(5)略wKr本库

第41~43页wKr本库

1.选择题wKr本库

(1)C(2)C(3)B(4)C(5)BwKr本库

2.填空题wKr本库

(1)(2，-3)(2)A‘(1，3)B(-1，-1)C(-3，-1)wKr本库

(3)700，400和400800和200或500和500wKr本库

(4)350(5)1080wKr本库

3.解答题wKr本库

(1)∵AD平分∠BACwKr本库

∴∠BAD=∠DAC=300wKr本库

∵AD=BDwKr本库

∴∠B=∠BAD=300wKr本库

∴∠C=1800-∠B-∠BAC=750wKr本库

∠ADB=∠DAC+∠C=1100wKr本库

(2)∵∠E+∠CDE=∠ACB=600wKr本库

∵CD=CEwKr本库

∴∠CDE=∠E=300wKr本库

BE=BC+CE=AB+1/2AC=15wKr本库

(3)略wKr本库

第41~43页wKr本库

1.选择题wKr本库

(1)C(2)C(3)B(4)C(5)BwKr本库

2.填空题wKr本库

(1)(2，-3)(2)A‘(1，3)B(-1，-1)C(-3，-1)wKr本库

(3)700，400和400800和200或500和500wKr本库

2008-2-1317:05回复wKr本库

chacousewKr本库

326位粉丝wKr本库

3楼wKr本库

(4)350(5)1080wKr本库

3.解答题wKr本库

(1)∵AD平分∠BACwKr本库

∴∠BAD=∠DAC=300wKr本库

∵AD=BDwKr本库

∴∠B=∠BAD=300wKr本库

∴∠C=1800-∠B-∠BAC=750wKr本库

∠ADB=∠DAC+∠C=1100wKr本库

(2)∵∠E+∠CDE=∠ACB=600wKr本库

∵CD=CEwKr本库

∴∠CDE=∠E=300wKr本库

BE=BC+CE=AB+1/2AC=15wKr本库

(3)略wKr本库

八年级数学寒假作业答案5wKr本库

第45-47页wKr本库

1.选择题wKr本库

(1)A(2)D(3)D(4)D(5)BwKr本库

2.填空题wKr本库

(1)24(2)((a-c)(b-c)(3)2x-3(4)6m+6nwKr本库

(5)–a+b-c(6)-4(7)14wKr本库

3解答题liuxue86.comwKr本库

(1)有问题wKr本库

(2)n+4=6n=2wKr本库

∵/m+n/=4/m-2/=4wKr本库

∴/m-2/=4wKr本库

∴m=6或m=-2wKr本库

∵1/2m2=2wKr本库

∴m=6(舍去)wKr本库

m=-2wKr本库

(3)①原式=-7a2-2a-b-3a2+2a-bwKr本库

=-10a2-2bwKr本库

②原式=-a2b-a2b+2a2b-1wKr本库

=-1wKr本库

③原式=3m2-4n2-mn+mn-4m2+3n2wKr本库

=-m2-n2wKr本库

(4)①原式=a-2a-b+3a-3bwKr本库

=2a-4bwKr本库

当a=-3b=2时wKr本库

原式=-6-8=-14wKr本库

②2A-B=-4x2+7x-14wKr本库

当x=-2时2A-B=-4(-2)2+7(-2)-14=-44wKr本库

(5)地砖面积=4y×4x-xy-2y×2xwKr本库

=11xywKr本库

所需费用：11xyawKr本库

(6)电脑原价1.y÷85%=20/7ywKr本库

2.当y=6800时原价=6800÷85%=8000(元)wKr本库

(7)a=10wKr本库

B=102-1wKr本库

=100-1wKr本库

=99wKr本库

a+b=10+99=109wKr本库

(8)3(2x2+3xy-2x-3)+6(-x2+xy+1)wKr本库

=6x2+9xy-6x-9-6x2+6xy+6wKr本库

=(15y-6)x-3wKr本库

∵3A-6B结果分X无关wKr本库

∴15y-6=0wKr本库

y=2/5wKr本库

第49-51页wKr本库

1.选择题wKr本库

(1)C(2)B(3)B(4)C(5)C(6)A(7)BwKr本库

2.填空题wKr本库

(1)am(2)mx(3)53-53(4)b5a12(5)297(6)1.2×1024wKr本库

(7)4x2y6z2(8)1(9)2891(10)-10/27a3b3(11)28a6(12)2wKr本库

3.解答题wKr本库

(1)①=-22×2×23wKr本库

=-26wKr本库

②=-(x+y)(x+y)(x+y)2wKr本库

=-(x+y)4wKr本库

③=(-1/3)3x6y9wKr本库

=-1/27x6y9wKr本库

④=(a22b)2wKr本库

=4a4b2wKr本库

⑤=x8+x8-x8-x8wKr本库

=0wKr本库

(2)3+x+2x+1=31wKr本库

3x=27wKr本库

x=9wKr本库

(3)2006÷4余2wKr本库

∴32006的末位数为9wKr本库

(4)2n=x3m×x2nwKr本库

(5)①<<<<<②nn+1<(n+1)n③<wKr本库

(6)①=n2+7n-n2-n-6∵n为自然数wKr本库

=6n-6∴n-1也为整数wKr本库

6n-6/6=n-1∴该式的值能被b整除wKr本库

②(x+a)(x+b)wKr本库

=x2+(a+b)x+abwKr本库

∴a+b=m=xwKr本库

Ab=36wKr本库

∴m=12wKr本库

第53-55页wKr本库

1选择题wKr本库

(1)D(2)B(3)B(4)C(5)C(6)C(7)C(8)C(9)BwKr本库

2.填空题wKr本库

(1)x3+y3(2)-3a-1(3)x=2(4)x4-1(5)100-1100+19999wKr本库

(6)-9a2+b2c2(7)2y2(8)-7p-q2(9)3(10)4m2+4m+1(11)x4-a4wKr本库

(12)a2-b2+2bc-c2wKr本库

3.解答题wKr本库

(1)①原式=a3b3ⅹa2b2ⅹa4b8c2=a9b12c2wKr本库

②原式=-3x2y2+3x3y+6x3y4-3xywKr本库

③原式=a3-a+3a2-3-2a3+8a2+a-4=-a3+11a2-7wKr本库

④原式=4m2-9n2wKr本库

⑤原式=y4-9x4wKr本库

⑥原式=(4x2-1)2=16x4-8x2+1wKr本库

(2)①原式=(1000+3)(1000-3)=999991wKr本库

②原式=2006/20062-(2006+1)(2006—1)=2006wKr本库

(3)原式=[x+(y+z)][x-(y+z)]=x2-(y+z)2=x2-y2-z2-2yzwKr本库

(4)全对wKr本库

(5)(x+y)2-(x-y)2=4xywKr本库

xy=[(2a)2-(2b)2]=a2-b2wKr本库

(6)(a-1/a)2=a2+1/a2-2a1/awKr本库

a2+1/a2=(a-1/a)2+2=16+2=18wKr本库

(7)(a+b+c)2=a2+b2+c2+2ab+2ac+2bcwKr本库

(2x-y+3z)2=4x2+y2+9z2-4xy+12xz-6yzwKr本库

第57～59页wKr本库

1选择题wKr本库

(1)A(2)C(3)D(4)D(5)A(6)C(7)A(8)A(9)C(10)D(11)CwKr本库

2.填空题wKr本库

(1)5C(2)-3x2z(3)4×103(4)15a3b2c(5)2(a+b)4(6)6x2y2-1(7)三次(8)10(9)a2b2wKr本库

3.解答题wKr本库

(1)①-1/2x2+3x-4.5②-2x2+3x-y③3/2x2y+5xy2-9/2(2)xm–n=xm÷xn=8÷5=1.6(3)9n=32n=232m-4n+1=32m÷34n×3=(3m)2÷(32n)2×3=36÷4×3=27wKr本库

(4)2x-1=0(5)a8÷a5÷a(6)a=(25)11b=(34)11c=(43)11`∵3211<6411<8111wKr本库

x=0.5=a2=3211=8111=6411∴awKr本库

(7)x=1/2原式=x3-x3+x4+1当X=1/2时,原式=(1/2)4+1=17/16wKr本库

=x4+1wKr本库

(8)原式4a2-4a+1当a=3/4时,wKr本库

原式=4(3/4)2-4×3/4+1wKr本库

=4×9/16-3+1wKr本库

=9/4-2wKr本库

=1/4wKr本库

第61~63页wKr本库

1.选择题wKr本库

(1)C(2)D(3)C(4)D(5)D(6)B(7)D(8)D(9)D(10)A(11)A(12)DwKr本库

2.填空题wKr本库

(1)(a+b)c(2)x(y-x)(3)a2b2(4)2z(x+y-z)(5)–my(6)210(7)2xy(x+2y)2wKr本库

(8)②④⑤⑥(9)(2a2+b-c)(2a2-b-c)(10)3a+b(11)a=b=c=1/3wKr本库

3.(1)①原式=(4xyz)2-32=(4xyz+3)(4xyz-3)wKr本库

②原式=[9(a+b)]2-[2(a-b)]2=(9a+9b+2a-2b)(9a+9b-2a+2b)=(11a+7b)(7a+11b)wKr本库

③原式=-3a(1-4a+4a2)=-3a(2a-1)2wKr本库

④原式=(a2+b2+2ab)(a2+b2-2ab)=(a+b)2(a-b)2wKr本库

(2)①原式=39x37-39x33=39(37-27)=39x10=390wKr本库

②原式=19.99(29+13-14)=(20-0.01)x28=560-0.28=559.72wKr本库

③原式=(897+896)(897-896)=1793wKr本库

④原式=(976+24)2=10002=1000000wKr本库

(3)原式=4[ab(a+b)-(a+b)]=4[2x(-4)+4]=-16wKr本库

(4)原式=2x(x2+3x-2)=0wKr本库

(5)原式=1+x[(1+x)+(1+x)2+.....+(1+x)2005wKr本库

=1+x(1+x)[1+(1+x)+…….+(1+x)2004]wKr本库

=1+x(1+x)2005x2005wKr本库

=1+2005x(1+x)2005wKr本库

(6)原式=(x2)2-2x2y2+(y2)2wKr本库

=(x2-y2)2wKr本库

=[(x+y)(x-y)]2wKr本库

当x=40y=50wKr本库

原式=(90x10)2=810000wKr本库

2008-2-1317:05回复wKr本库

59.172.114._4楼wKr本库

勒。。。。狠wKr本库

2008-2-1419:56回复wKr本库

222.64.60._5楼wKr本库

太强了，就不怕老师发现?wKr本库

这真的是一个“加速剂”哦(对某些人来说)wKr本库

2008-2-1515:01回复wKr本库

58.48.63._6楼wKr本库

我真的十分感谢，此时心情无法形容，大恩不言谢wKr本库

2008-2-1516:11回复wKr本库

chacousewKr本库

326位粉丝wKr本库

7楼wKr本库

怕什么，反正我上大学了.wKr本库

2008-2-1517:46回复wKr本库

yang8263011wKr本库

2位粉丝wKr本库

8楼wKr本库

(4)350(5)1080wKr本库

3.解答题wKr本库

(1)∵AD平分∠BACwKr本库

∴∠BAD=∠DAC=300wKr本库

∵AD=BDwKr本库

∴∠B=∠BAD=300wKr本库

∴∠C=1800-∠B-∠BAC=750wKr本库

∠ADB=∠DAC+∠C=1100wKr本库

(2)∵∠E+∠CDE=∠ACB=600wKr本库

∵CD=CEwKr本库

∴∠CDE=∠E=300wKr本库

BE=BC+CE=AB+1/2AC=15wKr本库

(3)略wKr本库

第45-47页wKr本库

1.选择题wKr本库

(1)A(2)D(3)D(4)D(5)BwKr本库

2.填空题wKr本库

(1)24(2)((a-c)(b-c)(3)2x-3(4)6m+6nwKr本库

(5)–a+b-c(6)-4(7)14wKr本库

3解答题wKr本库

(1)有问题wKr本库

(2)n+4=6n=2wKr本库

∵/m+n/=4/m-2/=4wKr本库

∴/m-2/=4wKr本库

∴m=6或m=-2wKr本库

∵1/2m2=2wKr本库

∴m=6(舍去)wKr本库

m=-2wKr本库

(3)①原式=-7a2-2a-b-3a2+2a-bwKr本库

=-10a2-2bwKr本库

②原式=-a2b-a2b+2a2b-1wKr本库

=-1wKr本库

③原式=3m2-4n2-mn+mn-4m2+3n2wKr本库

=-m2-n2wKr本库

(4)①原式=a-2a-b+3a-3bwKr本库

=2a-4bwKr本库

当a=-3b=2时wKr本库

原式=-6-8=-14wKr本库

②2A-B=-4x2+7x-14wKr本库

当x=-2时2A-B=-4(-2)2+7(-2)-14=-44wKr本库

(5)地砖面积=4y×4x-xy-2y×2xwKr本库

=11xywKr本库

所需费用：11xyawKr本库

(6)电脑原价1.y÷85%=20/7ywKr本库

2.当y=6800时原价=6800÷85%=8000(元)wKr本库

(7)a=10wKr本库

B=102-1wKr本库

=100-1wKr本库

=99wKr本库

a+b=10+99=109wKr本库

(8)3(2x2+3xy-2x-3)+6(-x2+xy+1)wKr本库

=6x2+9xy-6x-9-6x2+6xy+6wKr本库

=(15y-6)x-3wKr本库

∵3A-6B结果分X无关wKr本库

∴15y-6=0wKr本库

y=2/5wKr本库

第49-51页wKr本库

1.选择题wKr本库

(1)C(2)B(3)B(4)C(5)C(6)A(7)BwKr本库

2.填空题wKr本库

(1)am(2)mx(3)53-53(4)b5a12(5)297(6)1.2×1024wKr本库

(7)4x2y6z2(8)1(9)2891(10)-10/27a3b3(11)28a6(12)2wKr本库

3.解答题wKr本库

(1)①=-22×2×23wKr本库

=-26wKr本库

②=-(x+y)(x+y)(x+y)2wKr本库

=-(x+y)4wKr本库

③=(-1/3)3x6y9wKr本库

=-1/27x6y9wKr本库

④=(a22b)2wKr本库

=4a4b2wKr本库

⑤=x8+x8-x8-x8wKr本库

=0wKr本库

(2)3+x+2x+1=31wKr本库

3x=27wKr本库

x=9wKr本库

(3)2006÷4余2wKr本库

∴32006的末位数为9wKr本库

(4)2n=x3m×x2nwKr本库

(5)①<<<<<②nn+1<(n+1)n③<wKr本库

(6)①=n2+7n-n2-n-6∵n为自然数wKr本库

=6n-6∴n-1也为整数wKr本库

6n-6/6=n-1∴该式的值能被b整除wKr本库

②(x+a)(x+b)wKr本库

=x2+(a+b)x+abwKr本库

∴a+b=m=xwKr本库

Ab=36wKr本库

∴m=12wKr本库

第53-55页wKr本库

1选择题wKr本库

(1)D(2)B(3)B(4)C(5)C(6)C(7)C(8)C(9)BwKr本库

2.填空题wKr本库

(1)x3+y3(2)-3a-1(3)x=2(4)x4-1(5)100-1100+19999wKr本库

(6)-9a2+b2c2(7)2y2(8)-7p-q2(9)3(10)4m2+4m+1(11)x4-a4wKr本库

(12)a2-b2+2bc-c2wKr本库

3.解答题wKr本库

(1)①原式=a3b3ⅹa2b2ⅹa4b8c2=a9b12c2wKr本库

②原式=-3x2y2+3x3y+6x3y4-3xywKr本库

③原式=a3-a+3a2-3-2a3+8a2+a-4=-a3+11a2-7wKr本库

④原式=4m2-9n2wKr本库

⑤原式=y4-9x4wKr本库

⑥原式=(4x2-1)2=16x4-8x2+1wKr本库

(2)①原式=(1000+3)(1000-3)=999991wKr本库

②原式=2006/20062-(2006+1)(2006—1)=2006wKr本库

(3)原式=[x+(y+z)][x-(y+z)]=x2-(y+z)2=x2-y2-z2-2yzwKr本库

(4)全对wKr本库

(5)(x+y)2-(x-y)2=4xywKr本库

xy=[(2a)2-(2b)2]=a2-b2wKr本库

(6)(a-1/a)2=a2+1/a2-2a1/awKr本库

a2+1/a2=(a-1/a)2+2=16+2=18wKr本库

(7)(a+b+c)2=a2+b2+c2+2ab+2ac+2bcwKr本库

(2x-y+3z)2=4x2+y2+9z2-4xy+12xz-6yzwKr本库

第57～59页wKr本库

1选择题wKr本库

(1)A(2)C(3)D(4)D(5)A(6)C(7)A(8)A(9)C(10)D(11)CwKr本库

2.填空题wKr本库

(1)5C(2)-3x2z(3)4×103(4)15a3b2c(5)2(a+b)4(6)6x2y2-1(7)三次(8)10(9)a2b2wKr本库

3.解答题wKr本库

(1)①-1/2x2+3x-4.5②-2x2+3x-y③3/2x2y+5xy2-9/2(2)xm–n=xm÷xn=8÷5=1.6(3)9n=32n=232m-4n+1=32m÷34n×3=(3m)2÷(32n)2×3=36÷4×3=27wKr本库

(4)2x-1=0(5)a8÷a5÷a(6)a=(25)11b=(34)11c=(43)11`∵3211<6411<8111wKr本库

x=0.5=a2=3211=8111=6411∴awKr本库

(7)x=1/2原式=x3-x3+x4+1当X=1/2时,原式=(1/2)4+1=17/16wKr本库

=x4+1wKr本库

(8)原式4a2-4a+1当a=3/4时,wKr本库

原式=4(3/4)2-4×3/4+1wKr本库

=4×9/16-3+1wKr本库

=9/4-2wKr本库

=1/4wKr本库

第61~63页wKr本库

1.选择题wKr本库

(1)C(2)D(3)C(4)D(5)D(6)B(7)D(8)D(9)D(10)A(11)A(12)DwKr本库

2.填空题wKr本库

(1)(a+b)c(2)x(y-x)(3)a2b2(4)2z(x+y-z)(5)–my(6)210(7)2xy(x+2y)2wKr本库

(8)②④⑤⑥(9)(2a2+b-c)(2a2-b-c)(10)3a+b(11)a=b=c=1/3wKr本库

3.(1)①原式=(4xyz)2-32=(4xyz+3)(4xyz-3)wKr本库

②原式=[9(a+b)]2-[2(a-b)]2=(9a+9b+2a-2b)(9a+9b-2a+2b)=(11a+7b)(7a+11b)wKr本库

③原式=-3a(1-4a+4a2)=-3a(2a-1)2wKr本库

④原式=(a2+b2+2ab)(a2+b2-2ab)=(a+b)2(a-b)2wKr本库

(2)①原式=39x37-39x33=39(37-27)=39x10=390wKr本库

②原式=19.99(29+13-14)=(20-0.01)x28=560-0.28=559.72wKr本库

③原式=(897+896)(897-896)=1793wKr本库

④原式=(976+24)2=10002=1000000wKr本库

(3)原式=4[ab(a+b)-(a+b)]=4[2x(-4)+4]=-16wKr本库

(4)原式=2x(x2+3x-2)=0wKr本库

(5)原式=1+x[(1+x)+(1+x)2+.....+(1+x)2005wKr本库

=1+x(1+x)[1+(1+x)+…….+(1+x)2004]wKr本库

=1+x(1+x)2005x2005wKr本库

=1+2005x(1+x)2005wKr本库

(6)原式=(x2)2-2x2y2+(y2)2wKr本库

=(x2-y2)2wKr本库

=[(x+y)(x-y)]2wKr本库

当x=40y=50wKr本库

原式=(90x10)2=810000wKr本库

wKr本库

2023人教版八年级数学寒假作业答案相关文章：wKr本库

★ 2023八年级数学寒假作业答案大全wKr本库

★ 2023最新的初二数学寒假作业全部答案wKr本库

★ 初二上册寒假作业答案2023wKr本库

★ 语数英八年级上册寒假作业答案2023wKr本库

★ 初二上学期语数英寒假作业答案2023wKr本库

★ 2023初二寒假作业答案参考物理wKr本库

★ 2023八年级英语寒假作业最全的答案参考wKr本库

★ 八年级上册数学重要知识点试卷及答案参考2023wKr本库

★ 人教版八年级上册数学知识点考试试卷及答案参考wKr本库

★ 2023年初二寒假作业语文答案参考wKr本库