已知x+y=5,xy=6求(x+1)(y-1)

已知x+y=5,xy=6求(x+1)(y-1)


x=5-y
(5-y)*y=6
x=-6 y=-1
(x+1)(y-1)=10



已知x—xy=5,xy—y=-3,求x+y—2xy的值.


由題得:X=5+XY Y=XY+3
所以:X+Y=8+2XY
得:X+Y-2XY=8+2XY-2XY=8



已知X-Y=-3,XY=2,則2XY-X+Y的值是
要求有解題過程或解題中的想法,答案已經知道,就是不知道如何去理解,要符合初一的知識.


2xy-x+y
=2xy-(x-y)
=2x2-(-3)
=7



一元一次方程應用題公式(詳細)
要詳細的公式.全面的.
要行程…搭配…等…公式啊……


速度X時間=路程
工效X時間=工作總量
單價X數量=總價
單產量X數量=總產量
ax²;+bx+c=0
當b²;-4ac>=0時有兩個根
x1=(-b+√(b²;-4ac))/2a
x2=(-b-√(b²;-4ac))/2a
當b²;-4ac



一項工作,l/2小時完成了12.5%,照這樣計算,這項工作全部完成需要幾小時?


1÷(12.5%÷1/2)
=4小時



4.5立方分米=()昇()毫升


4.5立方分米=(4)昇(500)毫升
1立方分米=1昇=1 000毫升



人教版英語七年級下册十一單元知識點
要全的,快,拜託了


Unit 11知識點講解
元片語1.. TV shows(電視節目)soap opera sitcom(situation comedy)a comedy an action movie a documentary a thriller
cartoon drama(戲劇)Beijing Opera talk show Animal World Tell it like it is Law Today game show CCTV News News in 30 Minutes Man and Nature nese Cooking Around China Lucky52 arts news sports show Culture China Weekend Talk週末話談2.write an article for the school magazine.給學校雜誌寫一篇文章3.a thirteen -year - old boy.一個十三歲的男孩4.wear colorful clothes.穿著顏色鮮豔的衣服5.interview sb.採訪某人in fact.實際上6. wear scarves.戴著圍巾7 .think of想起,考慮到二.重點句型1. What do you think of soap operas/ sports shows?I can't stand / don't mind / like/love/hate/them. 2. What does she think of“Hilltop High”/Amanda?She doesn't like it/her.三.重難點解析
1. What do you think of…?你認為…怎麼樣?(談論對某事物的喜好程度)可選擇的回答有:(1)I like it.(2)I don't mind it.(3)I don't like it.(4)I can't stand it.(5)I like it very much.(6)I love it.(7)It's beautiful.(8)They're fantastic How about的用法區分. 1. wear(v.動詞)“穿,戴,佩”.根據不同賓語,翻譯不同的漢語意思.
wear earrings戴耳環wear a dress穿連衣裙wear a watch戴手錶
wear a beard蓄鬍子wear long hair留長髮
2. think“想,考慮,思索”(v.動詞)可以和許多介詞搭配,組成新的意思. A:think of“考慮”;“有…的看法”,有時等於think about.
What does he think of Beijing Opera?他對國劇有什麼看法?My mother always thinks of everything!我媽媽總是想到所有的東西. B:think about“考慮”(指計畫,觀念,看它是否相宜、可行)He is thinking about going to China.他正在考慮去中國.
3. too與either的區別too“也”,表示肯定意義,與肯定的表達方法連用;而either“也不”,表示否定意義,與否定的表達方法連用.(1)—My brother likes to play soccer.我哥哥喜歡踢足球.—I do,too.我也是(喜歡).
(2)—My brother doesn't like to play soccer.我哥哥不喜歡踢足球.—I don't,either.
我也不喜歡.
also也可以表示“也”,但一般情况下,too和either放在句子之後,also放在動詞之前.
We also love talk shows.我們也喜歡訪談節目. 4. a thirteen - year - old boy一個十三歲的男孩此結構中,year用單數形式,且用連字號,這構用作定語.e.g a five - month - old baby一個五個月大的嬰兒a one-way road a three-metetree 200-word-long article 5. enjoy(v.喜愛,享受)enjoy後面接名詞、代詞或動名詞,與like/ love用法的區別.like/ love還可以接動詞不定式(toI enjoy the soap operas.我喜愛肥皂劇. I enjoy watching the soap operas.我喜愛看肥皂劇.但我們不能說:I enjoy to watch the soap operas.只能說:I like / love to watch the soap opera6. Welcome to sp.歡迎來到…. Welcome to China. Welcome home(省掉介詞)Welcome n. The people in Tibet gave me a warm welcome.西藏的人們熱烈地歡迎了我. Welcome adj. You are welcome. A welcome movie star.一個受歡迎的電影明星. 7. stand表示忍受(多用於否定句、疑問句can’t stand sth/ doing sth.不能忍受某事/做某事Hecan't stand the hot weather.他忍受不了炎熱的天氣.Can you stand the soap opera?你忍受得嗎?I can’t stand staying at home all the day long.我不能忍受一整天都呆在家裡. 8.mind介意/在乎mind sth/doing sth. I don’t mind the cold.
Do/Would you mind my having breakfast in the classromm/ opening the window?不介意:Never mind/Not at all;介意,反對:I’m sorry/Sorry,but I do. 9. find students who agree with you.找出同意你的同學. A:定語從句的引入:指人時用Who/that.指物時用which/that.
The girl is Emmy. The girl is wearing a colourful dress. The girl who is wearing a colourful dress is Emmy. Can you find my pen that/which I bought last weekend?B:agree with sb. agree on sth(意見suggestion,plan)agree with sb on sth.在…上同意某人.
I agree with him. I agree with him on this problem. Do you agree on my suggestion?你同意的意見嗎?
Agree to do sth.同意做某事. He agreed to go to the movies with me. 10. ask students about fashion. ask sb sth.問某人某事ask sb aout sth.問某人關於某事
You can ask me questions after class. You can ask me about soap operas. Ask sb to do sth.要求某人做某事:Teachers often ask us to do a lot of homework. fashion,n流行,時尚.fashion show,時裝秀Fashion store in fashion流行的,out of fashion不流行的
11. I showed each students six things. A:show sb sth. show sth to sb(當sth是it,them等時,只能用show it/them to sb.)
B:each每個(代詞),各自的(adj).與every(adj)的區別.
Each可指兩個或三個以上的每一個,every只指三個以上的每一個. Each(one)of us. Every one of us我們當中的每一個. 12. some of their answers are interesting .
Some of/ a lot of/ most of/ each of/ every one of/ many of/ much of
13.Here are their likes and dislikes. Here is+單數,Here are+複數
14. article in the school magazine,文章在書,magazine上用in,在newspaper/paper上on.
15.Can you please put my letter in next month’s magazine?
A:Can/Could/will you please do sth?表示委婉的請求,建議,Can you please not do sth?
B: put放sth +介詞短語.
put the book on my desk. Put the food in the fridge.
相關搭配:put on穿上,put down.放下,put up舉起,put away把…收起來放好. 16. I can’t stand the idea that old people can’t be beautiful. A:idea表示主意,想法,建議等.可數名詞
That’s a good idea.好主意= That sounds great/good. I have an idea/ no idea
17. clothes clothing cloth區別:Clothes,指具體的衣服,不能用作單數,也不能和數詞連用.不能說a clothes,five clothes Girls like beautiful clothes.
clothing是衣服、服裝的總稱,是集體名詞,沒有複數形式.,a piece of clothing一件衣服
意Clothing can keep us warm.衣服可以保暖.意思是“布料”、“毛料”、“絲綢”(特別指布料和毛料).Cloth在一般情况下是物質名詞,數. the piece of cloth .
tablecloth桌布,就可數a tablecloth.



口袋裏有1個紅球、1個黃球、1個白球.從口袋裏任意摸出1個球,摸到球的顏色一共有()種不同的可能.
A. 1種B. 2種C. 3種


口袋裏有1個紅球、1個黃球、1個白球.從口袋裏任意摸出1個球,摸到球的顏色一共有紅、黃、白3種不同的可能.故選:C.



500公頃等於多少平方千米?3公頃等於多少平方米


500公頃=5平方千米,3公頃=30 000平方米



猜燈謎
靠下麵來複習.()
出力樂悠悠.()
自己多心不發火,剛一發火火氣無.()
四面圍欄,請勿入內()
一個是犬不像犬,一個非犬倒像犬()
放進兩粒丸,製成兩粒丹.()
1.由6個正方體達成的立體,從正面看形狀是□
□□□□
從左面看形狀是□
□□
這個立體是什麼形狀?最少需要多少個正方體?最多需要幾個?
2.一個球從高空落下,第一次彈起27米,第二次彈起18米,第三次彈起12米,第四次彈起8米,第五次彈起多少米?
3.一個棱長6釐米的正方體塗成紅色,切成8塊,各小塊沒塗顏色的面積之和是多少平方釐米?
4.甲乙丙作同一輛車,說好大家分攤車資,甲在1/3處下車,乙在
2/3處下車,丙坐到終點,共付90元錢,甲乙各應給丙多少車費?
數學第1題不清楚應該是
由6個正方體達成的立體,從正面看形狀是□
··················□□□□
從左面看形狀是□
·······□□
·=空格
lydia_leung,算式


燈謎:第一個是不是“翡”字第二個是“嘉”字第三個是不是“熄”字第四個是“囫”字第五個是“猶”字第六個是“册”字數學第一題圖不是說由六個正方體達成麼,沒什麼可以命名的形狀吧,用六個擺剛剛好啊.第一排並排四…