\(\sqrt{2x-3}=5\)

là 14 nhak mk vừa giải xong đúng ko gì bằng

\(27^8-3^{21}=\left(3^3\right)^8-3^{21}=3^{24}-3^{21}=3^{21}.\left(3^3-1\right)=3^{21}.26\) chia hết cho 26

\(8^{12}-2^{33}-2^{30}=8^{12}-\left(2^3\right)^{11}-\left(2^3\right)^{10}=8^{12}-8^{11}-8^{10}\)

\(=8^{10}.\left(8^2-8-1\right)=8^{10}.55\)

hình như đề sai ở câu sau nhé bn,chia hết cho 55 thôi

413.21

EX2: Find the mistake
I If it doesn't rain heavily, we could finish our work

-> can
2 If you didn’t keep calm you can't passing your driving test

->pass
3 Unless they took a map , they couldn't lose their way

->could
4 if you want to attend the course , you had to pass the examination

->have
EX3: GIVE CORRECT FORM OF VERBS
l . Tourists could see fish ( swim) along the brook.

->swimming
2. We enjoy (swim) along this river.

->swimming
3.The form teacher has asked Jack (write)an essay on the Thames.

->to write
4. It sometimes may be difficult (get) a taxi during rush- hours.

->to get
5. The rain has made the children ( stop)their games.

->stop
6.She tells the driver ( take)her to the railway station.

->to take
7.Does Mrs Green have them ( carry)those books back home?

->to carry
8. The principal noticed those pupils (try)harder and harder.

->to try
9.Children have just stopped ( play)football.

->playing
10.They keep ( talk)about an old friend they met yesterday.

->talking
11 .Is Black Pool (visit) by thousands of tounsts each year?

->visited
12. We heard Mr Brown ( park)his car near the gate.

->parking
13. They’ve finished ( do)their homework.

->to do
14. They had their house (paint)before Tet holiday.

->painted

deu chia het ca

=69999

a, nếu x là số chẵn

b, nếu x là số lẻ

\(\sqrt[4]{840}\)\(\approx\)5,3835

=> 4 số đó nằm trong khỏng từ 2 đến 8

trong đó có các nhóm: 2,3,4,5  ;  3,4,5,6  ;  4,5,6,7  ;  5,6,7,8

trong các nhóm đó, chỉ có nhóm thứ 3 (4,5,6,7) có tích = 840

Vậy 4 số tự nhiên đó là 4,5,6 và 7

1970+9805=11775

. Choose one word whose underlined part is pronounced differently from the others. Identify your answer by circling the corresponding letter A, B, C or D.

1. A. study B. much C. century D. button

2. A. nothing B. clothes C. hold D. told

3. A. hear B. heart C. near D. clear

4. A. ache B. mechanic C. chemistry D. approach

5. winter B. win C. wine D. windy

II. Choose the best answer to complete each of the following sentences.

6. She stayed here and enjoyed ................... classical music.

A. listen B. listening C. to listening D. to listen

7. How ................. the fire..................?

A. do/ make B. do/ made C. is/ make D. is/ made

8. Is there .................... you want me to do while you’re out?

A. anything B. something C. any things D. some things

9. I was cooking dinner ..................the phone ...................

A. then/ rang B. then/ was ringing C. when/ rang D. when/ was ringing

10. The teacher ............... a class at 8 o’clock yesterday evening.

A. is having B. was having C. has D. has had

11. ................I was having reading newspapers, my husband was watching T.V.

A. While B. If C. Because D. As

12. She said that she ........................ swimming in the sea in autumn.

A. has liked B. likes C. liked D. was liking

13. On Christmas Eve, people often ......................... a tree.

A. are decorated B. were decorated C. decorating D. decorate

14. Have you ever been too Phong Nha ................. in Vietnam?

A. Place B. Cave C. Reef D. Bay

15. He asked me ................. I liked coffee.

A. which B. as C. whether D. what