\(x+\left(x+1\right)+\left(x+2\right)+...+\left(x+99\right)=5450\)

\(\left(x+x+x+...+x\right)+\left(1+2+...+99\right)=5450\)

Từ 1 đến 99 có số số hạng là:

     (99-1):1+1=99 (số hạng)

Tổng các số từ 1 đến 99 là:

     (99+1).99:2=4950

⇒\(\left(x\cdot100\right)+4950=5450\)

⇒\(x\cdot100=5450-4950\)

⇒\(x\cdot100=500\)

⇒\(x=500:100\)

⇒\(x=5\)

Vậy \(x=5\)

x+x+1+x+2+.....+x+99=5450

(x+x+...+x)+(1+2+....+99)=5450

100x+4950=5450

100x=5450-4950

100x=500

      x=500:100

      x=5

vậy x=5

My favorite sport is basketball 🏀. I love the fast-paced nature of the game and the teamwork involved in scoring points. The adrenaline rush of making a shot or stealing the ball is exhilarating. Playing basketball not only keeps me physically fit but also helps me develop important skills like communication and strategy.

Dịch : Môn thể thao yêu thích của tôi là bóng rổ 🏀. Tôi yêu tính chất nhịp độ nhanh của trò chơi và tinh thần đồng đội để ghi điểm. Cảm giác hưng phấn khi thực hiện cú sút hoặc cướp bóng thật phấn khích. Chơi bóng rổ không chỉ giúp tôi có thể lực tốt mà còn giúp tôi phát triển những kỹ năng quan trọng như giao tiếp và chiến lược.

1 Some programs on TV are becoming very popular with children
2 The earth is getting warmer and warmer
3 Clair is very sociable. She knows a lot of people
4 She spent her childhood in the country
5 I am an energetic person. I play a lot of sports and run every day
6 There is a beautiful bridge in the city centre
7 The president will make a speech tonight
8 Her parents encouraged her to apply for the job
9 I understand clearly what you are saying
10 Artists are creative people

1 popular

2 warmer

3 sociable

4 childhood

5 energetic 

6 beautiful

7 speech

8 encouraged

9 clearly

10 creative

1.She works at a sports shop now.

2.I'm sure they will lose the match.

3.He never tidies his room; it's always a mess.

4.When she comes into the living room, she always changes the channel on the TV.

5.The farmers are having a lot of trouble with foxes at present.

6.The next term starts next week.

7.Sarah often works late at the office.

8.Tien Minh is good at playing badminton.

9.You shouldn't put too much salt in the soup.

10.Ann is making a dress for herself at the moment.

1.She works at a sports shop now.

2.I'm sure they will lose the match.

3.He never tidies his room; it's always a mess.

4.When she comes into the living room, she always changes the channel on the TV.

5.The farmers are having a lot of trouble with foxes at present.

6.The next term starts next week.

7.Sarah often works late at the office.

8.Tien Minh is good at playing badminton.

9.You shouldn't put too much salt in the soup.

10.Ann is making a dress for herself at the moment.

1 The judge convinced that the man was (to be) guilty
2 My father does not like (not like) skiing
3 Three days are not (not to be) long enough for a good holiday
4 They may use (use) this room for the classroom
5 You must clean the wall before you paint (paint) it
6 The audience listened (listen) to everything he said last night
7 Sometimes she gets up before the sun rises (rise)
8 They are preparing (prepare) the Christmas dinner at the moment
9 He worked (work) in a bank when he lived in London
10 We will start (start) our plan next week

1.The judge convinced that the man ____was__(to be) guilty.

2.My father ___doesn't like___(not like) skiing.

3.Three days___isn't___(not to be) long enough for a good holiday.

4.They may___use___(use) this room for the classroom.

5.You must clean the wall before you _paint____(paint) it.

6.The audience___listened___(listen) to everything he said last night.

7.Sometimes she gets up before the sun____rises__(rise).

8.They____is preparing__(prepare) the Christmas dinner at the moment.

9.He____worked__(work) in a bank when he lived in London.

10.We ___are going to start___(start) our plan next week.

1 Jane likes to wear colourful clothes
2 He is a good student
3 We must be quick. We have little time
4 She acted too badly
5 Nam speaks English fluently
6 I am terribly sorry. I am late
7 He feels happy in his new club
8 I tried on my shoes and they fitted me perfectly
9 It's extremely cold
10 It's kind of you to help me

1.Jane likes to wear ________(colourful/colourfully) clothes.

2.He is a ________(good/well) student.

3.We must be ________(quick/quickly).We have little time.

4.She acted too ________(bad/badly).

5.Nam speaks English ________(fluently/fluent)

6.I am ________(terrible/terribly) sorry.I am late.

7.He feels ________(happy/happily) in his new club.

8.I tried on my shoes and they fitted me ________(perfect/perfeetly)

9.It's________(extreme/extremely) cold.

10.It's ________(kind/kindly) of you to help me.

• Món chính: Bát cơm nguyên hạt hoặc bát ngũ cốc hạt lựu với sữa không đường.
• Phụ phẩm: Một quả chuối hoặc một quả táo.
• Nước uống: Một cốc nước trái cây tự nhiên không đường hoặc một cốc nước lọc.

• Món chính: 150g thịt gà nướng hoặc hấp.
• Rau sống: Salad gồm rau xanh như rau diếp, cà chua, dưa leo, và ăn kèm một số hạt giống như hạt hạnh nhân hoặc hạt óc chó.
• Cơ bản: 1 chén cơm gạo nâu hoặc 200g khoai lang nướng.
• Nước uống: Nước lọc hoặc trà xanh không đường.

• Món chính: 200g cá hồi nướng hoặc hấp.
• Rau sống: Rau bina, cà chua, cà rốt trong một bát salad.
• Cơ bản: 1 chén cơm gạo lứt hoặc 200g bún tươi.
• Tráng miệng: Một ổ cam hoặc một ổ dứa.
• Nước uống: Nước lọc hoặc nước trái cây tự nhiên không đường.

Đảm bảo rằng mỗi bữa ăn đều có sự kết hợp của các nhóm thực phẩm như protein, tinh bột, rau củ, và trái cây để cung cấp đầy đủ chất dinh dưỡng cho cơ thể. Đồng thời, điều chỉnh lượng calo theo nhu cầu năng lượng của bạn để duy trì sức khỏe và cân nặng ổn định.

\(\dfrac{4}{3\cdot7}+\dfrac{4}{7\cdot11}+\dfrac{4}{11\cdot15}+...+\dfrac{4}{198\cdot202}\) (*sửa tí ở phân số đầu tiên nhé !)

\(=\dfrac{1}{3}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{11}+...+\dfrac{1}{198}-\dfrac{1}{202}\)

\(=\dfrac{1}{3}+\left(-\dfrac{1}{7}+\dfrac{1}{7}\right)+\left(-\dfrac{1}{11}+\dfrac{1}{11}\right)+...+\left(-\dfrac{1}{198}+\dfrac{1}{198}\right)-\dfrac{1}{202}\)

\(=\dfrac{1}{3}+0+...+0-\dfrac{1}{202}\)

\(=\dfrac{1}{3}-\dfrac{1}{202}\)

\(=\dfrac{199}{606}\)

\(\dfrac{2}{3\cdot5}+\dfrac{2}{5\cdot7}+\dfrac{2}{7\cdot9}+...+\dfrac{2}{37\cdot39}\)

\(=\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+...+\dfrac{1}{37}-\dfrac{1}{39}\) 

\(=\dfrac{1}{3}+\left(-\dfrac{1}{5}+\dfrac{1}{5}\right)+...+\left(-\dfrac{1}{37}+\dfrac{1}{37}\right)-\dfrac{1}{39}\)

\(=\dfrac{1}{3}-\dfrac{1}{39}\)

\(=\dfrac{13}{39}-\dfrac{1}{39}\)

\(=\dfrac{12}{39}\)

\(\dfrac{x-1}{21}=\dfrac{3}{x+1}\)

\(\Rightarrow\left(x-1\right)\left(x+1\right)=3\cdot21\)

\(\Rightarrow x^2+x-x-1=63\)

\(\Rightarrow x^2-1=63\)

\(\Rightarrow x^2=63+1\)

\(\Rightarrow x^2=64\)

\(\Rightarrow x^2=8^2\)

\(\Rightarrow x=\pm8\)

Vậy: ...

x-1/21 = 3/x+1

=> (x-1)(x+1) = 21.3

=> x^2 - x + x - 1 = 63

=> x^2 - 1 = 63

=> x^2 = 64

=> x = ±8