1、 第6课时 因式分解 中考考什么A(a+3)(a-3)a(b+2)(a+b)21.(2017北部湾模拟)多项式x2-4分解因式的结果是（）A.（x+2）（x-2）B.（x-2）2C.（x+4）（x-4）D.x（x-4）2.(2017钦州一模)分解因式：a2+2ab+b2=.3.（2016南宁）分解因式：a2-9=.4.（2016钦州）分解因式：ab+2a=.核心考点解读把一个多项式化为几个整式的 的形式，这样的式子变形叫做这个多项式的因式分解，也叫做把这个多项式分解因式.因式分解积 因式分解的基本方法1.提公因式法：如果多项式的各项有公因式，可以把这个公因式提取出来，将多项式写成公因式与另一个
2、因式的乘积的形式，这种分解因式的方法叫做提公因式法.pa+pb+pc=p(a+b+c).2.公式法（1）两个数的平方差，等于这两个数的和与这两个数的差的积.a2-b2=.(2)两个数的平方和加上（或减去）这两个数的积的2倍，等于这两个数的和（或差）的平方.a2+2ab+b2=;a2-2ab+b2=.(a+b)(a-b)(a+b)2(a-b)2x2+（p+q）x+pq=（x+p）（）（x+q）十字相乘法：怎么考1下列各式由左到右的变形中，属于分解因式的下列各式由左到右的变形中，属于分解因式的是（是（）A a（x+y）=ax+ayBx24x+4=x（x4）+4C 10 x25x=5x（2x1）Dx
3、216+6x（x+4）（）（x4）+6x C C焦点1 因式分解的概念1.下列各式由左边到右边的变形中，属于因式分解的是（）A.a(x+y)=ax+ayB.x2-4x+4=x(x-4)+4C.10 x2-5x=5x(2x-1)D.x2-16+6x=(x+4)(x-4)+6xC对应训练命题规律主要考查分解因式的概念，常以选择题形式呈现.方法指导因式分解是把一个多项式分解成几个整式乘积的形式，注意：分解的是多项式；整式；积.焦点2 因式分解样题2 分解因式：ax+ay=.a（x+y）解析观察等式的左边，提取公因式a即可求得答案.变式训练2.（2016 百色）分解因式：16-x2=（）A.（4-x）
4、（4+x）B.（x-4）（x+4）C.（8+x）（8-x）D.（4-x）23.(2016梧州)分解因式：2x2-2=（）A.2（x2-1）B.2（x2+1）C.2（x-1）2 D.2（x+1）（x-1）AD命题规律考查分解因式的意义与两种基本的分解因式的方法.以选择题和填空题呈现，题目常以提公因式法和公式法结合的分解因式为主.方法指导（1）pa+pb+pc=p(a+b+c);（2）a2-b2=(a+b)(a-b);（3）a2+2ab+b2=(a+b)2,a2-2ab+b2=(a-b)2.补充练习 1分解因式：2a2 6a=2下列分解因式正确的是（B）A3x2-6x=x（3x-6）B-a2+b2
5、=（b+a）（b-a）C4x2-y2=（4x+y）（4x-y）D4x2-2xy+y2=（2x-y）23分解因式：2a28=4分解因式：3a212ab+12b2=2a（a3）2（a+2）（）（a2）3（a2b）2 7.下列多项式中，能用提公因式法分解因式的是下列多项式中，能用提公因式法分解因式的是()A.x x2 2-y-y B.x x2 2+2x+2x C.x x2 2+y+y2 2 D.x x2 2-xy+y-xy+y2 2 5.分解因式：分解因式：3x3x2 2-3=-3=.6.分解因式：分解因式：X X2 2+2xy+y+2xy+y2 2-4=-4=.3(x+1)(x-1)3(x+1)(
6、x-1)(x+y+2)(x+y-2)(x+y+2)(x+y-2)B8.分解因式：分解因式：a a2 2-4a+4=-4a+4=.(a-2)(a-2)2 29.9.分解因式：分解因式：a a3 3+2a+2a2 2+a=+a=.10.10.将下列式子因式分解将下列式子因式分解 x-x x-x2 2-y+y-y+y2 2=.a(a+1)2(x-y)(1-x-y)(x-y)(1-x-y)11.关于关于x的一元二次方程的一元二次方程x x2 2+bx+c=0+bx+c=0的两根为的两根为x x1 11 1，x x2 22 2，则，则x x2 2+bx+c+bx+c分解因式的结果为：分解因式的结果为：.
7、12.分解因式：分解因式：x x2 2-4y-4y2 2+x-2y=+x-2y=.(x-2y)(1+x+2y)(x-2y)(1+x+2y)（x-1x-1）(x-2)(x-2)一、完形填空(共15小题；每小题1分，满分15分)阅读下面短文，掌握其大意，然后从每题所给的A、B、C、D四个选项中选出最佳选项。Life is full of the unexpected._1 1_a cold winter afternoon，a man saw an old lady standing by her expensive car and clearly she needed help.So he st
8、opped and _2 2_ his old truck.“Is he going to hurt me?He doesnt look safe，”the old lady was _3 3_(B B)1.1.A.In BOn CAt DUnder(D D)2.2.A.went off Bturned off Ctook off Dgot off(C C)3.3.A.glad Bexcited Cworried Dsurprised The man could see that she was afraid，so he said in his friendliest_4 4_，“Im her
9、e to help you，madam.Why dont you_5 5_ in the car where its warm？_6 6_，my name is Ted Johnson.”Ted quickly fixed the car and the lady thanked him.Then she asked _7 7_ she should pay him.(A A)4.4.A.voice Bsound Cnoise Dlook(A A)5.5.A.wait Bto wait Cwaited Dwaits(D D)6.6.A.In a way BOn my way CUnder th
10、e way DBy the way(B B)7.7.A.how many Bhow much Chow far Dhow often But Ted wanted_8 8_ money.He was just giving a hand to someone in trouble._9 9_ was normal for him to do such a thing like that.He said，“If you really want to repay(报答)me，next time you see someone in need，think of me and help them.”(
11、B B)8.8.A.not Bno Csome Dany(C C)9.9.A.This BThat CIt DThey After saying goodbye，the lady continued down the road until she reached a small_1010_where she decided to stop for something to eat.As the pretty waitress took her order，the lady noticed she was _1111_ eight months pregnant(怀孕)The waitress
12、looked tired and weak，_1212_she was very kind.As the lady was going to pay the$10 bill，she remembered Teds words.(A A)10.10.A.restaurant Bbookstore Ccinema Dlibrary(C C)11.11.A.mostly Bhardly Cnearly Dseldom(B B)12.12.A.so Bbut Cor Dthough After the lady was gone，the waitress saw a small note on the
13、 table.It said，“Somebody once helped me the way Im helping you.Continue being kind to other people.”Under the note were five _1313_ dollars.The waitress was_1414_ excited that she called her husband to tell him the news，“TedTed Johnson my dear youre not going to believe _1515_ just happened”(A A)13.
14、13.A.hundred Bhundreds Chundred of Dhundreds of(D D)14.14.A.too Bvery Csuch Dso(C C)15.15.A.how Bwhen Cwhat Dwhy二、阅读理解(共15小题；每小题2分，满分30分)阅读下面四篇短文，从每题所给的A、B、C、D四个选项中选出最佳选项。A A(20172017广东中考改编)(C C)16.16.The World Poetry Day is on _ AAugust 28th BMarch 3rd CMarch 21st DAugust 28th(D D)17.17.The purpose
15、 of the World Poetry Day is _Ato encourage the British to write poemsBto teach children how to read and write poemsCto raise money for the poets from all over the worldDto help people to read，write and teach poems better(A A)18.18.The rules for the competition include the following EXCEPT_Athat poet
16、s can write poems in any languageBthat poets must use their unpublished poemsCthat poems cant be written on the subject of violence or drugsDthat poems cant be taken back after the competitionB B Sports can help you keep fit and close to nature.However，whether you are on the mountains，in the waves，o
17、r on the grassland，you should realize that sport you choose might have great influence on the environment.Some sports are resourcehungryGolf，as you may know，eats up not only large areas of countryside，but also lots of water.Besides，huge amounts of energy are used to keep its courses(球场)in good condi
18、tion.This causes major environmental changes.For example，in the dry places of Portugal and Spain，golf is often held responsible for(为承担责任)serious water shortage(短缺)in some local areas.There are many environmentfriendly sports.Power walking is one of them that you could take up today.You dont need an
19、y special equipment except a good pair of shoes，and you dont have to worry about resources and your purse.Simple and free，power walking can also help you stay healthy.If you walk regularly，it will be good for your heart.Experts say that 20 minutes of power walking daily can make you feel less anxiou
20、s，sleep well and keep thin.Whatever sport you take up，you can make it greener than by using environmentfriendly equipment and buying products made from recycled materials.But the final goal should be“green gyms”They are better replacements(替代)for traditional health clubs and modern sports centers.Me
21、mbers of green gyms play sports outdoors，in the countryside or other open spaces.There is no special requirement for you to start your membership(会员身份)And best of all，its free.(A A)19.19.Which of following does the author most probably support according to the passage?ABicycling around the lake.BCar
22、 racing on the road.CPlaying basketball in a gym.DSwimming in a sports centre.(D D)20.20.What does the underlined phrase“resourcehungry”in this passage mean in Chinese?A广为流行的 B亲近自然的C低成本的 D耗费资源的(C C)21.21.The author uses power walking as an example mainly because_Ait is an outdoor sport Bit is loved
23、by many peopleCit uses fewer recourses Dit is supported by experts(B B)22.22.The author writes the passage to _Ashow us disadvantages of golfBurge us to take part in green sportsCexplain the major sports influence of popular sportsDdiscuss different kinds of environmentfriendly sport C C Lao She wro
24、te Teahouse in 1957.The play shows the audience life in China between 1898 and 1945.It takes place in a teahouse in old Beijing and it tells us the story of Wang Lifa and his customers.It asks us to see the teahouse as the centre of the neighbourhood.Finally，it says goodbye to old Beijing and its pe
25、ople.The story starts in 1898 during the Qing Dynasty.It continues in 1916，and finally，it brings the audience to the end of the AntiJapanese War in 1945.After the war，Wang loses the teahouse and he dies.Lao She was born in Beijing in 1899.His parents sent him to the Teachers School in Beijing and he
26、 learned to teach.From 1924 to 1929 he taught Chinese to the English in London.He wrote many plays，novels and short stories.He was named a“Peoples Artist”and a“Great Master of Language”He was one of the greatest Chinese writers of the 20th century.In Lao Shes Teahouse today，waiters bring tea to the
27、customers and sell them delicious Chinese food.If you like Beijing Opera，folk music，acrobatics or magic shows，you can enjoy them in the teahouse.Lao Shes Teahouse gives a wonderful welcome to everyone from China and from all over the world.(B B)23.23.Whats the main idea of Paragraph 4?ALao She.BLao
28、Shes Teahouse.CThe story of Teahouse.DThe play Teahouse.(D D)24.24.How many years of life in China is shown in the play Teahouse?A57 years.B45 years.C98 years.D47 years.(A A)25.25.Lao She was all of the following except _Aa boss of TeahouseBa Peoples ArtistCa Great Master of Language Done of the gre
29、atest Chinese writers of the 20th century(C C)26.26.Who were welcome to Lao Shes Teahouse today?AOnly Chinese customers.BOnly foreign customers.CEvery customer from home and abroad.DOnly Beijing Opera audience.D DSpecial Bridges Help Animals Cross the RoadSpecial Bridges Help Animals Cross the RoadR
30、eported by Sheila Carrick Why did the chicken cross the road?To get to the other side.Most people know this joke.But recently，some people have been much more worried about how the grizzly bear(灰熊)and mountain lion can cross the road.“Millions of animals die each year on US roads，”the Federal Highway
31、 Administration reports.In fact，only about 80 ocelots，an endangered wild cat，exist in the US today.The main reason?Road kill.“Ecopassages(生态通道)”may help animals cross the road without being hit by cars.They are paths both over and under roads.“These ecopassages can be extremely useful，so that wildli
32、fe can avoid road accidents，”said Jodi Hilty of the Wildlife Protection Society.But do animals actually use the ecopassages?The answer is yes.Paul Beier of Northern Arizona University found foot marks left by mountain lions on an ecopassage that went under a highway.This showed that the lions used t
33、he passage.Builders of ecopassages try to make them look like a natural part of an area by planting trees on and around them.Animals seem to be catching on.Animals as different as salamanders(火蜥蜴)and grizzly bears are using the bridges and underpasses.The next time you visit a park or drive through
34、an area with a lot of wildlife，look around.You might see an animal overpass!(D D)27.27.The writer uses the example of“ocelots”to show that _Awild animals have become more dangerousBthe driving conditions have improved greatlyCthe measure for protecting wildlife fails to workDan increasing number of
35、animals are killed in road accidents(D D)28.28.From the passage，we know an ecopassage is _Aan underground path for carsBa fence built for the safety of the areaCa bridge for animals to get over a river Da path for animals to cross the road(B B)29.29.When the writer says that“Animals seem to be catch
36、ing on”，he means _Aanimals begin to realize the dangers on the road Banimals begin to learn to use ecopassagesCanimals are crossing the road in groupsDanimals are increasing in number(D D)30.30.The writer asks visitors and drivers to look around when travelling because_Awild animals may attack cars
37、Bwild animals may jam the roadCthey may see wild animals in the park Dthey may see wild animals on ecopassages三、词汇运用(共15小题；每小题1分，满分15分)A用方框中所给词语的适当形式填空。每词限用一次。3131Mr Li has made a_decisiondecision_ to travel to Beijing.3232The school_providesprovides_ the students with delicious food every day.3333H
38、e just sat_inin_silencesilence_ and didnt say any words.3434I have been to several_EuropeanEuropean_ countries，such as England and France.3535You cant go _acrossacross_ the street when the traffic lights turn red.B根据短文内容和所给中文提示，在空白处写出单词的正确形式。每空限填一词。It is 8：30 am at the Chengdu Research Base.Lin Wei，
39、a panda keepers，is preparing the milk for the baby pandas 36.36._breakfastbreakfast_(早餐)At 9：00 am，she finds that most of the babies are already 37.37._awakeawake_(醒着的)and hungry.When the babies see the keepers，they run over with excitement，and some of them even 38.38._walkwalk_(行走)into their friend
40、s and fall over!Theyre so cute and lovely.Lin Wei takes care of them like theyre her 39.39._ownown_(自己的)babies.She washes，feeds and plays with them every day.Pandas do not have many babies，maybe only one every two years.The babies often 40.40._diedie_(死亡)from illnesses and do not live very long.Adul
41、t pandas spend more than 12 hours a day eating about 10 kilos of bamboo.Many years ago，there were a lot more bamboo forests and pandas in China.But now pandas are in great 41.41._dangerdanger_(危险)People cut down many bamboo trees so they are losing their homes.There are about 1，590 42.42._wildwild_(
42、野生的)pandas living in the forests in Sichuan，Shaanxi and Gansu provinces.Another 200 or so live in zoos or research centres in China and other countries.Its a 43.43._pitypity_(遗憾)that many people dont know that.So the government has set up an education programme in Chengdu.It teaches children in citi
43、es about p a n d a s，and tells them about the 44.44._importanceimportance_(重要性)of saving the pandas.But t e a c h i n g c h i l d r e n i s o n e w a y t o h e l p 45.45._protectprotect_(保护)environment and save pandas.The Chinese government is also planting more bamboo trees so there will be more fo
44、rests for pandas to live in.We all hope that in the future there will be a lot more pandas than now.四、语法填空(共10小题；每小题1分，满分10分)阅读下面短文，在空白处填入一个适当的词，或填入括号中所给单词的正确形式。Some people still live in their home town.However，others may only visit 46.46._itit_once or twice a year.Millions of Chinese leave the coun
45、tryside 47.47._toto_searchsearch_(search)for work in the cities.Among these is Hua Xing.He 48.48._hashas_livedlived_(live)in Wenzhou for the last 13 years.With a hard job 49.49._inin_ a factory，he seldom visits his home town.“I havent been back 50.50._forfor_ three years.Itsa shame，”he says.51 51_De
46、velopmentsDevelopments_(develop)have been good in Hua Xings home town since 2002，for example，new roads 52.52._havehave_appearedappeared_(appear)A new school 53.53._hashas_beenbeen_builtbuilt_(build)However，some things will never change in his home town.The big old tree is still beside the playground
47、.Children in his time 54.54._usuallyusually_(usual)liked to play together under it.It was 55.55._suchsuch_ happy childhood.五、(20172017邵阳中考)任务型阅读(共5小题；每小题1分，满分5分)阅读下列短文，在空白处(5660)填入与短文内容相符的信息，完成阅读摘记。Maciek Czastka was born in Lodz，Poland.He came to China several years ago.So far，he has been working i
48、n Chengdu for three years.“The Belt and Road Initiative(一带一路的倡议)is meaningful，”he said.“Thanks to it，we are offered more chances.”The most powerful support for Chengdu to thrive(兴盛)along the Belt and Road is the ChengduEurope express railway(高速铁路)It provides direct train services between Chengdu and
49、 the city of Lodz.Because of the express railway，trains can bring things from China to Europe.At the same time，they can bring back European food，wine，meat and so on.In 2016，a total of 460 trains ran between Chengdu and Europe.The number is expected to grow to 1，000 this year.Since the ChengduLodz ex
50、press railway was opened.Chengdu，together with other cities in west China，has developed close trade ties with the European country.Poland is one of the largest apple producers in Europe.Czastkas company helps farmers in Poland sell their apples to China.More and more European products will be sent t
