Do n+3\(⋮\)n+3 (*) => (n+3)²\(⋮\)n+3 hay n²+6n+9\(⋮\)n+3

=> n²+6n+9-(n²-7)\(⋮\)n+3 hay 6n+16\(⋮\)n+3

Từ (*) => 6n+18\(⋮\)n+3

=> 6n+18-(6n+16)\(⋮\)n+3 hay 2\(⋮\)n+3

=> n+3 \(\in\){-2;-1;1;2}

Vậy n \(\in\){1;2;4;5}

Ta có: \(n^2-7⋮n+3\Leftrightarrow n^2-9+2⋮n+3\Leftrightarrow\left(n-3\right)\left(n+3\right)+2⋮n+3\)

\(\Rightarrow\)\(2⋮n+3\)

Vậy n+3 là Ước của 2

Ta có bảng sau: 

Vậy n=....

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1. If you take my advice, you .............will be.......... (be) happy.
2. What would you do if you ...........were............. (be) me?
3. If you .............lend........... (lend) me some books I will give them back in two weeks.
4. I ...............would have sent......... (send) her a letter if I had found her address.
5. She .............would not have stolen ........... (not/steal) the bread if she hadn't been hungry.
6. If she ..............comes.......... (come) here I will tell her about the film.
7. I will be unhappy if you ..............leave.......... (leave) me.
8. If you hadn't been so crazy you ..........would not have bought.............. (not/buy) this expensive house.
9. If the sun .............shines........... (shine) I will go to the beach.
10. If I ..............won.......... (win) the lottery I would leave my country.

1. If you take my advice, you ..........will be.............. (be) happy.
2. What would you do if you ...........were............. (be) me?
3. If you ............lend............ (lend) me some books I will give them back in two weeks.
4. I ...........would have sent............. (send) her a letter if I had found her address.
5. She ...........wouldn't have stolen............. (not/steal) the bread if she hadn't been hungry.
6. If she ...........comes............. (come) here I will tell her about the film.
7. I will be unhappy if you ...........leave............. (leave) me.
8. If you hadn't been so crazy you .............wouldn't have bought........... (not/buy) this expensive house.
9. If the sun ..........shines.............. (shine) I will go to the beach.
10. If I ...........won............. (win) the lottery I would leave my country.

47.wears; won't stay

48. touch ; won't scream

49 will forget ; don't phone 

50.will remember ; give

51 .help; will do

52.will water; stays 

53. has; will buy

54.offer ; will take 

55 will have ; live

Chào em, em tham khảo nhé!

47) If Claire wears (wear) this dress at the party, our guests won't stay (not stay) any longer.

48) If I touch (touch) this snake, my girlfriend won't scream. (not scream).

49) She will forget (forget) to pick you up if you (not phone) don't phone her.

50) I will remember(remember) you if you give (give) me a photo.

51) If you help (help) your grandma, I will do (do) the shopping.

52) Andrew will water(water) the flowers if he stays (stay) at home.

53) If she has (have) 5 pounds more, she will buy (buy) herself this T-shirt.

54) If they offer (offer) me the job, I will take (take) it.

55) You will have (have) summer holidays from June till August if youl ive (live) in the USA.

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47) If Claire.........wears...........(wear) this dress at the party, our guests............willnot stay.......................(not stay) anylonger.

48) If I........touch......(touch) this snake, my girlfriend....willnot scream.............(not scream).

49) She........will forget....(forget) to pick you up if you (not phone) …don't phone……….her.

50) I......will remember..............(remember) you if you......give...............(give) me a photo.

51) If you....help.......(help) your grandma, I.........will do..........(do) the shopping.

52) Andrew........have water.......(water) the flowers if he.........stayed........(stay) at home.

53) If she.........has............(have) 5 pounds more, she.......will buy............(buy) herself this T-shirt.

54) If they........offer............(offer) me the job, I……will take………............(take) it.

55) You.....will have...(have) summer holidays from June till August if you....live..(live) in the USA

1/ If you want to cook rice, you should learn how to cook rice.

2/ If you want to do sums, you should learn Maths.

3/ If you want to be warm, you should wear more clothes.

Chào em, em tham khảo nhé!

1.l can't finish this task if you don't give me a hand.

=> Unless you give me a hand, I can't finish this task.

2.You will run out of money if you don't stop wasting it.

=> Unless you stop wasting money, you will run out of it.

3.Don't call me unless it is an emergency.

=> If it is not an emergency, don't call me.

4.James will not pass the test unless he studies harder.

=> If Jame doesn't study harder, he will not pass the test.

5.If Jane finishes her work before 6 pm, she will dine out with her friends.

=> Unless Jane finishes her work before 6 pm, she will not dine out with her friends.

6. Unless my brother finds a companion, he won't go travelling this summer

7. If you don't listen attentively to the teacher, it is not easy to do these exercises

8. Unless Jim submit his essay before Tuesday, he will be punished by the teacher

1, I can't finish this task if you don't give me a hand. 

2, If you stop wasting money you will run out of it.

3, Don't call me if it isn't an emergency 

4,Jame won't pass the test if he studies harder.

5,Jane will dine out with her friends if she finishes her work before 6 pm.

6,My brother doesn’t find a companion if  he won’t go travelling this summer

7, It is not easy to do these exercises if you listen attentively to the teacher

8, Jim will be punished by the teacher if he doesn’t submit his essay before Tuesday 

1. will send

2. won't steal

3. comes

ĐIỀN VÀO CHỖ TRỐNG

- I .will send .... (Send) her a letter if I had found her address

- She .won't steal.. (not/steal) the bread if she hadn't been hungry

hc tốt 

- will send

-won't steal / will not steal

-comes

-leave

-won't buy / will not buy

-shines

-win

GOOD LUCK

tick nhìu cho tôi

1. We (do) ___________will do_______ this for you if you (want) __want______.
2. If we (need) ____________need_______ some help, we ( ask) ___will ask_____.
3. If Peter (stay) ___stays____ with his grandparents, Susan (not be) ____won't be____ happy.
4. If we (win) ____win____ the money, we (buy) _____will buy__________ a new house.
5. She (not write) ________won't write_______________ to you if she ( leave) __leaves_.
6. We (go) ___________will go________ on holiday if there ( be ) __is___ time.

7. If we_____plant_____(plant) more trees, the air_____will be______(be) fresher.

8. If the soil_____is______(be) polluted, the vegetables______will die_______(die).

9. Unless he______calls______(call) me, I_______will stay________(stay) at home.

10. If the weather ( be ) __is___ very good, we (go)___will go__out  this afternoon.

11. If a student____recycles_____(recycle) the papers, he____will save_____(save) energy.

12. If we ( invite ) _______invite_________she ( attend ) ______will attend____our meeting.

13. We ( keep ) _____will keep____fit if we ( ride ) ____ride____bicycles to school.

15. If she ( have ) _____has____time  , she ( attend) _will attend____our party.

16. There ( not, be ) ____won't be_____accidents if people ( be ) __are___careful on the road.

17.  If we ( continue ) ___continue____destroying the environment, our life ( be ) __will be___destroyed.

18. She ( be ) ____will be_____happy if you ( visit ) ____visit____her tonight.

19. If people ( watch ) ___watch_____TV too much, their life ( be ) ___will be____affected.

20. He ( win ) ____will win____the gold medal if he ( practice ) ______practices___hard.

1. will do- want

2. need- will ask

3. stays- will not be

4. win- will buy

5. ko hiểu rõ lắm

6. will go-is

7. plant- will be

8. is- will die

9. calls- will stay

10. is- will go

11. recycles- will save

12. invite- will attend

13. will keep- ride

15. has- will attend

16. will not be- ko rõ

17. continue- will be

18. will be- visit

19. watch- will be 

20. will win- practices