Cho tứ giác ABCD có AC=AD.Chứng minh:BC<BD

Viết các biểu thức sau dưới dạng tích:

a)\(m^2-n^2\) c)-16+\(\left(x-3\right)^2\)

b)\(\left(x^2+x-1\right)^2-\left(x^2+2x+3\right)^2\) d)64+16y+\(y^2\)

Put in the correct form of the verbs:

1.Mrs.Green (take)....................Alice to the dentist many times.

2.My sister always (wash).....................her hands before meals.

3.Hurry up!The train (come).................in.

4.I hope it (not rain)...................in the dry season.

5.He (sleep)........................so he didn't understand what you said.

6.Will you wait a minute while i (look).......................through the text?

7.You must tell me what you (do)........................since i last saw you.

8.An economic critic often (follow)..................the war.

9.You (witness)...........................many things by the time you die.

10.So far you (make)................no mistakes on this exercise.

11.What you (do).................at 7 p.m yesterday?

12.We didn't recognize him.He (change)...................a lot.

13.He discovered to his horror that he (eat).................a fly.

14.Where you (spend).................your holiday last year?

15.He (do).......................nothing before he saw me.

16.All of them (sing)...................when i came.

17.She constantly (invite)........................me to lunch and dine with her once or twice a year.

18.They had sold all the books when we (get)............there.

19.Why didn't you listen while i (speak)...................to you.

20.Where are you?-I'm upstairs.I (have)................a bath.

B1.Viết lại câu:

1.It is one-fifty.

=>It is ten............

2.What's the matter with you?

=>(wrong).............

3.Why were you absent from class last Monday?

=>Why didn't............................

4.Liz thought no fish was more beatiful than the colorful little fish.

=>(the most)............

5.Long is bad swimmer.

=>Long swims.............

6.Mrs.Oanh cook well.

=>Mrs.Oanh is...............

7.Ann drives dangerously.

=>Ann is......................

8.It is not necessary for you to finishthe work to day.

=>You don't have.................

9.Ilike roller skating anh my brother does,too.

=>(so)................................

10.How much are these rackets?

=>How much do....................?

11.Literature interests my brother a lot

=>(interested)...............................

12.Nam like staying at home than going to the zoo

=>(prefers)................................

13.Let's visit the beautiful Khmer temples of Angkor Wat this summer

=>How about...........................

14.Listening to music at home is more interesting than going to the concert

=>I prefer......................

15.We didn't enjoy the trip becauseof the heavy rain

=>The heavy rain prevented................................

16.You shouldn't eat too many candies

=>You 'd............................

17.He is a slower and more careful driver than i am

=>He drives...............

B1: Verb form

1.I don't mind(get)...........up early.

2.I can't stand(laugh).........with his joke.

3.What about .............Ha Long Bay?(visit)

4.I need ........... you.(measure)

5They must'n forget.................other things.(do)

6.She would like...............a new house.(buy)

7.Remember.......................your teeth(brush)

8.Don't forget...........................(phone)your mother.

9.Mathew suggested............(go)out for a meal but i wanted..........................(stay)at home.

10.She doesn't allow.............................(smoke)in the house.

11.I tried.................(give)up......................(take)sugar in my tea but i didn't like it.

12.I am hoping............(stop)..............(work)at the factory soon.

B2:Complete the following sentences with"because (of)","(al)though/even though/despite/in spite of".

1._________________he worked hard,he didn't receive any praise.

2.He ate the chocolate cake____________________he is on diet.

3.____________the high prices,my daughters insist on going to the movies every Saturday.

4.____________________it was cold,i went out.

5.___________________John didn't study hard,he succeeded.

6.We took many picture________________________________the cloudy sky.

7.______________her poor memory,the old womwn told interesting stories to the children.

8.She went home early____________________she didn't feel well.

9.I couldn't get to sleep___________________the noise.

10.The students arrived late______________the traffic jam.

chữ suy ra đổi thành dấu giùm mình nha.

Các số thêm độ vô hộ nha

Th2: Xét 2 tia oy và oz thuộc hai nửa mặt phẳng chứa tia ox

      suy ra tia ox nằm giữa hai tia oz và oy

suy ra xoy + xoz = yoz

suy ra 60 + 30 = yoz

suy ra yoz = 90

Vậy yoz = 90 hoặc yoz = 30

Tìm x,y biết:

\(4x^2\)+\(10y^2\)+12xy+20x+22y+41=0