八年级寒假作业答案深圳报业集团出版社修改

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八年级寒假作业答案深圳报业集团出版社修改

实数:

一:1.C(第3 5 6) 2.C

二:3.±根号五 4.2倍根号2 5.1

三、计算

1. 2倍根号2 (提示:把后面的都化简成有根号2的,则是3倍根号2+4倍根号2-5倍根号2=2倍根号2)

2. 根号三 (提示:先把上面的2个相乘,再把上下根号化成整体根号的分数,分数的.结果又可直接变3,所以为根号3)

3. 14+4倍根号3 (提示:前面是平方差公式[(A-B])*(A+B)=A平方-B平方),后面是完全平方公式[(A+b)平方=A平方+B平方-2AB][A B皆

是常数]把公式代如即可求出答案)

4.6 (提示:[任何数的0次方皆=1] 先把2倍根号12化成有根号3的则根号12变为2倍根号3,再与前面的2相乘得4倍根号3。4倍根号3与根号3相加得5

倍根号5,再除下面的根号3则=5,再与后面的1相加,得6。)

四:[短除法http://baike.baidu.com/view/915249.html?wtp=tt]

(1)短除法

分解后,59319由3个3、3个13相乘得来。

3×3×3×13×13×13=59319

于是乎,将一个3和一个13配对,得到

3×13×3×13×3×13=59319

39×39×39=59319

(2)首先他是3的倍数,那他就是27的倍数,59319/27=2197

2197不是3的倍数,而只有3的立方末尾是7,所以他可能是13的3次方,果然他是13的立方,所以他是39的立方

平移:

一:1.A 2.A

二:3.7.5 4.60°

三:5略 6.(1)略 (2)因为是旋转(不改变形状大小)且三角形ABC是正三角形(3边相等,角为60度)所以AD=BC

BC=AB 角DAC=角ACB 所以AD平行BC (内错角)所以四边形ABCD是菱形(临边相等的平行四边形是菱形)7。如图

四边形(1)

一:C D

二: 18倍根号3 16 3

三:

连接DE FB 因为四边形ABCD是平行四边形

所以DO=BO AO=CO

又因为E F是AO CO的中点,

所以OE=OF

在三角形EOB和三角形DOF中

因为角DOF=BOE OE=OF OD=OB

所以三角形EOB全等三角形DOF

所以DF=EB

(接下:)

[法1:所以角DFO=角OEB,所以BE平行DF 既BE 平行且相等DF]

[法2:同理得DE=FB 所以四边形DFBE是平行四边形,所以DF平行EB,既BE 平行且相等DF]

四:B

四边形(2):

一:A C

二:12 0〈A〈(或等于)2倍根号13 4倍根号2+2 根号2+1

三:

连接DB

因为四边形ABCD是菱形

所以AD=CD AD平行BC DC平行AE

又因为角DAB=60

所以角CBE=60

所以角DCB=60

所以角DBC=60 角DBA=60(菱形对角线平行一对对角,因为其中一角=60所以另一角为120 再被平分就等于60)

所以角ACB=30 (菱形对角线平行一对对角,因为该角=60所以另一角为30)

又因为CE垂直AC

所以角BCE=60

在三角形CDB和三角形CEB中

因为角BCD=角BCE=60 角CBE=角CBD=60 CB=CB

所以三角形CDB全等三角形CEB

所以AD=DC=CE

又因为DC平行AE 且EA不平行CE

所以四边形AECD是等腰梯形。

四:提示:做HY(使AH=CY)

其中测试:

一:BDB

二:4 3 5 8 25 12 16 246

三:

(1)3[提示:先把上面的乘进去,得根号18,再与下面的根号2结合,得根号18/2 得根号9,=3]

(2)0[提示:把根号12变出有根号3的(2倍根号3)

(3)12-根号6[提示:后面是平方差公式[(A-B])*(A+B)=A平方-B平方),前面是完全平方公式[(A+b)平方=A平方+B平方-2AB][A B皆是

常数]把公式代如即可求出答案]

(4)14倍根号2 [提示:把后2项变出都根号2的(根号8=2倍根号2 7倍根号18=7*3倍根号2=21倍根号2)

确定位置:

一:CBA

二:北偏东60度500米处 7

三:A(1,4)B(-2,3)C(-3,0)D(3,0) 16

一次函数(1):一:DAC二:(1)(2)(5)(6) 2 (1.5,0) (0,-3) 增大 2.25 (0,

6) 三:[1]略[2](2/3,0)(0,2)[3]2.5 [4]当X〈

2/3 时 Y》0 当X〉2/3时Y《0

一次函数(1)

一:DAC

二:(1)(2)(5)(6) 2 (1.5,0) (0,-3) 增大 2.25 (0,6)

三:[1]略[2](2/3,0)(0,2)[3]2.5 [4]当X〈

2/3 时 Y》0 当X〉2/3时Y《0

一次函数(2)

一:AD

二:-3 [一二四] Y=2X+6

三:甲 2/3 四:[1]10 [2]1.2 [3] 50KG

综合

一:BBBA

二:0 0 (1,1) 拉伸 4

三:17.4

二元(1)

一:DCC

二:[1]X=0.5 Y=-1 [2]X=-3 Y=0

三:设牛单价X元 羊单价Y元 得式子:3X+2Y=3400 X+5Y=3300

Y=500

二元(2)

一:CB

二:2 含未知数项 -2 3

三:[1]X=3 Y=5 [2]N=-2 M=5 四:设原来的数为10X +Y 得式子:X+Y=7

-(10Y+X)

=-27 求得:X=2 Y=5 既原来数为25

求得X=800 (10X+Y)

英语

happy1

P37.一

what a melody(悦耳) song it is!

what a fast boy he is !

what a heavy girl she is !

what a beautiful school it is !

what a good boy he is !

what a beatific(幸福) boy he is!

P37第二题

is cleaned

were taken

is made

was given

be being show

was invited

was stole,was fond…

turtle

tiger

japan

Mexico

tiger

sierra leone

P39.一:

better best

more most

bigger biggest

more smart most smart

more badly most badly

more carefully most carefully

more slowy most slowy

more healthy most healthy

hotter hoyyest

farer farest

P40一: havier heaviset older oldest more expensive most expensive better known best known less leas fewer fewest thinner thinnest more easily most easily oftener oftenest larger largest

plan to do 计划做某事 He planned on taking his vacation in July.

hope to do 希望做某事 We hope to see you soon.

agree to do 同意做某事 No results found for agree to do.

refuse to do 拒绝做某事 She asked him for a loan, but he refused.

finish doing 完成某事(后面就不打某事..到时记得自己加上哈)Have you finished reading that magazine?

enjoy dong 擅长….I enjoyed reading these books very much.

practise doing 练习…I practise my swing.

suggest doing 建议..I suggest our going to the park on Sunday

admit doing.承认… I admitted breaking the window.

deny doing否认…He denied having seen these watches before.

arrange for 安排…I’ve arranged for a taxi.

offer to do 提供They offered to help me

like/love+doing喜欢.. She likes playing the piano

hate to do 遗憾…He hated to have quarrelled with her.

hate to do 讨厌 He hated to have quarrelled with her.

remember to do 记住去做某事 Do you remember her telephone number?

remember doing 记得做过某事 I remember telling you about it once.

forget to do 忘记去做某事 I forgot posting the letter.

forget doing 忘记做过某事 Don’t forget to post the letter.

p43

动词 过去式 过去分词

be was been

cook cooked cooked

know knew known

swim swan swam

get got got

teach tought taught

leave left left

fell felt felt

smell smelt smelt

drive drove driven

run ran run

think thought thought

keep kept kept

buy bought bought

begin began began

do did done

cost cost cost

find found found

throw threw throw

stand stood stood

speak spoke spoken

come came come

give gave given

hear heard heard

send sent sent

hurt hurt hurt

see saw seen

steal stole stolen

take took taken

sleep slept slept

sit sat sat

meet met met

bring brought brought

fly flew flown

wake woke waken

choose chose chosen

lose lost lost

read read read

rise rose risen

wear wore worn

P50

三.

Early to bed

Get up early to exercise every day

To eat less fatty food and more milk.

Do not eat too many sweet can cause obesity.

In the case of hot weather drink plenty of water.

Can not drink beverages,drink plenty of water.

In the winter changes according to the right to add their own clothes to not cath a cold The eyes will not watch TV much,so choose the appropriate time watching TV. Playing games in not good for mental and physical,we need to less play.

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