1) Do morning excises and you will have a healthy body

2 ) One of our longest vacation is Thanksgiving

3) My neighbors are concerning about the environtment

1. I have more books than Hoa has.

2. I work fewer hours than Hoa works.

3. I have less money than Lan has.

a) Thanh / live / in the city

Does Thanh live in the city?

b) they / stay / in her house

Do they stay in her house?

c) Lan / have/ big bedroom

Does Lan have a big bedroom?

d) you / work / at night?

Do you work at night?

e) Ngan / like / math

Does Ngan like math?

f) Hoa / live / in a flat

Does Hoa live in a flat?

\(\frac{8}{15}và\frac{9}{16}\)

C1 : \(1-\frac{8}{15}=\frac{7}{15}\)

\(1-\frac{9}{16}=\frac{7}{16}\)

1. Loan burnt her hand while she was cooking (cook) dinner.

2. I (meet) met a friend while I was doing (do) the shopping.

3. I (pay) was paying for my things when I (hear) heard someone call my name.

4. I (turn) was turning round and (see) saw Phan.

5. While he (have) was having a drink, a waiter (drop) dropped a pile of plates.

6. While the waiter (pick) was picking up the broken plates, he (cut) cut his finger.

7. We (take) were taking a short test when the earthquake (begin) began.

8. Mr.Lan (read) was reading the newspaper while his wife (prepare) was preparing dinner.

9. The fire (break) broke out when they (work) were working on the twentieth floor of the skyscraper.

10. The car (travel) was travelling at high speed when it (strike) stroke the child.

\(C=x^2+2y^2-2xy-4y+5=\left(x^2-2xy+y^2\right)+\left(y^2-4y+4\right)+1\)

\(=\left(x-y\right)^2+\left(y-2\right)^2+1\ge1\)

Đẳng thức xảy ra khi x = y = 2

Vậy min C = 1 khi x = y = 2

bài 3 nah không biết đúng hông nữa 

n=20a20a20a=20a20a.1000+20a=(20a.1000+20a).1000+20a=1001.20a.1000+20a

theo đề bài n chia hết cho 7,mà 1001 chia hết cho 7 nên 20a chia hết cho 7

ta có 20a = 196+(4+a),chia hết cho 7 nên 4 + a chia hết cho 7 .Vậy a = 3

I don't like tea.

He doesn't play football in the afternoon.

You don't go to bed at midnight.

They don't do the homework on weekends.

The bus doesn't arrive at 8.30 a.m.

My brother doesn't finish work at 8 p.m.

Our friends don't live in a big house.

The cat doesn't like me.

Bạn học thì quá khứ đơn chưa nhỉ? Doraemon