Bài 1: Gọi số có 2 chữ số cần tìm có dạng \(\overline{ab}\) (a \(\in\)N*; b\(\in\)N; a, b\(\le\) 9)

Theo bài ra ta có: a-b=5 (1) và \(\overline{ba}=\frac{3}{8}\overline{ab}\)

=> 10b+a=\(\frac{3}{8}.10a+\frac{3}{8}.b\) => \(\frac{77}{8}b=\frac{11}{4}a\) => \(\frac{a}{b}=\frac{7}{2}\) (2)

Từ(1) và (2) => a=7, b=2

Vậy số cần tìm là 72

Bài 2: Gọi số có 2 chữ số cần tìm có dạng \(\overline{ab}\) (a \(\in\)N*; b\(\in\)N; a, b\(\le\) 9)

Theo bài ra ta có : a-b=2 (1) và \(\overline{a0b}-\overline{ab}=630\)

=> 100a+b-10a-b=630 => 90a=630 => a=7

Thay a=7 vào (1) => 7-b=2 => b=5

Vậy số cần tìm là 75

1. Student have Vietnamese lessons on Saturdays

2. English and America students don't have lessons on Saturdays.

3. They have classes only in the morning on weekdays.

4. Vietnamese students have summer vacation off tree months.

5. The students have their exam in May.

6. They always do their homework in the evening.

7. She is watching television at the moment.

8. They don't enjoy going to the concert.

9. My father starts work at seven thirty.

10. Most teenagers like to go to the parties.

tick mình nha!!!

1. Let/ go / cafeteria/ and / get / cold drink.
---> Let's go to the cafeteria and get a cold drink.

2.Lan / be / music room / now / and / learn / play / guitar .

----> Lan is in the music room now and learning to play the guitar

3. How often / sister / practise / piano / Youth Club?
---> How often does your sister practise the piano in Youth club ?

4. Your group / rehearse / play / school anniversary celebrations / present?
---> Is your group rehearsing to play in the school anniversary celebrations in the present ?

5.Tom / spend / most / time / lie / couch / front / TV.
---> Tom spends most of his time lying on the couch in front of TV.

6. If / you / tired / watch TV / come / me.
---> If you felt tired, you should stop watching TV and come to me.

8.You / going / sell / house / and / move / capital?
---> Are you going to sell your house and moving to the capital ?

7.. There / not be / good movies / show / moment.
---> There are not good movies on the show at the moment.

9. You / like / go / movies / me / tonight ?

---> Do you like to go to the movies with me tonight?

10.How / father / always / travel / work / everyday ?

--->How does your father always travel to work everyday ?

"Ferocious crocodiles plunge into the hotel pool attacking female guests

The Daily Mail has published video recording frightening spectacle of ferocious crocodiles plunge into a swimming pool in the hotel in Kariba, Zimbabwe.

Crocodile 2m long passed the fence and crawl to swim. When you see a couple is swimming in the pool, the crocodile has plunged.

While boys hurry to jump ashore, the girls have to fight with the alligator aggressive. She was lucky to avoid the bites of alligators before climbing ashore. She proved to be extremely frightened. "

living

vòng tuần hoàn phổi và vòng tuần hoàn cơ thể

do phản xạ ánh sáng

Ta có: EM//AC => EM//AD

MD//AB => MD//AE

=> AEMD là hình bình hành

I là trung điểm của ED => I là trung điểm của AM => I thuộc AM

=> AIM=180

m^3+3m-3m^2+1=(m-1)^3=(101-1)^3=100^3

số bạn chỉ thích văn là : 25-18=7 (bạn)

số bạn chỉ thích toán: 29-18=11(bạn)

số bạn trong lớp đó là : 11+7+18=36(bạn)