1. We are used to driving on the left in England

2. My family have been to HCM city for several times

3.By the time you got to the party, they had prepared everything

4. I hope she will be pretty when she grows up

5. I wonder what has happened there since we left

6. Geogle goes on holiday every two years

7. When Queen Victoria died in 1910, she was resigning for over 60 years

1. Three o'clock/ yesterday afternoon/ man / woman/ climb/ mountain/ Scotland.

=>At about three o'clock yesterday afternoon,a man and a woman were climbing up a mountain in Scotland.

2. Sun/ shine/ sky/ clear.

=> The sun was shining and the sky was clear.

3. Woman/ think/ storm/ come.

=> However, the woman thought that the storm was coming.

4. She / want / turn back/ companion/ not.

=> she wanted to turn back but her companion did not.

5. She / persuade / return/ with/ her.

=> She tried to persuade him to return with her.

6. He / refuse / go / alone.

=> He refused and went on alone.

7. Storm/ come /he / trap/ mountain/ night.

=> The storm came and he was trapped in the mountain during the night.

8. Rescue team/send/ help/ him.

=> A rescue team was sent to help him.

9. Thep/ spend/ four hours/ look/ him.

=> They spent four hours looking for him.

10. Lucky/ morning/ he/ rescue/ helicopter / take / hospital.

Luckily, this morning he was rescued by a helicopter and taken to hospital.

a)

Ta có :A=27⁵=27.27.27.27.27                                                 Ta có :B=243³=243.243.243

               =(3.3.3).(3.3.3)...(3.3.3)(có 5 nhóm)                                      =(3.3.3.3.3).(3.3.3.3.3)...(3.3.3.3.3)(có 3 nhóm)

               =3.3.3.3.3...3(15 thừa số 3)                                                 =3.3.3.3.3...3.3(có 15 thừa số 3)

               =3¹⁵                                                                                                               =3¹⁵

Mà3¹⁵=3¹⁵

Nên 27⁵=243³

=>A=B

b)Ta có:A=8⁵=8.8.8.8.8                                                            B=2⁷

               =(2.2.2).(2.2.2)...(2.2.2)(có 5 nhóm)

               =2.2.2.2.2.2..2(có 15 thừ số 2)

Mà 2¹⁵>2⁷

Nên 8⁵>2⁷

=>A>B

c)(bạn tự tìm người giải ,mình bó)

d)A=1+2+2²+2³+2⁴+..+2¹⁹⁹⁹                                                                                               B=2²⁰⁰⁰

 2.A=2.(1+2+2²+2³+...+2¹⁹⁹⁹⁾

2.A=2+2²+2³+2⁴+...+2¹⁹⁹⁹+2²⁰⁰⁰

Ta có:2.A-A=(2+2²+2³+2⁴+...+2²⁰⁰⁰) - (1+2+2²+2³+...+2¹⁹⁹⁹)

      A=2²⁰⁰⁰-1

Mà  2²⁰⁰⁰-1<2²⁰⁰⁰

Nên A<B

Câu2:

A=4+4²+4³+4⁴+...+4⁶⁰

4.A=4.(4+4²+4³+...+4⁶⁰)

4.A=4²+4³+4⁴+...+4⁶⁰+4⁶¹

4.A-4=(4²+4³+4⁴+...+4⁶¹)-(4+4²+4³+...+4⁶⁰)

A=\(\frac{4^{61}-4}{3}\)

bài 3 thì mình quên cách làm rồi để mai mình xem vở chỉ cho