what are you writing????????

My name is John. I am 23 years old. I am from Sydney, Australia. I study mechanical Engineering at the university of Sydney. I can speak three languages, French, Italian, and English. I have three brothers and one sister. My dad is a doctor and my mom is a teacher. In my free time I to play football and basketball. I cooking Italian food such as, spaghetti and pasta. In the weekends I to go to the beach.

Cần gấp

\(\left|2x-1\right|-3=11\)

=> \(\left|2x-1\right|=11+3\)

=> \(\left|2x-1\right|=14\)

=> \(\orbr{\begin{cases}2x-1=14\\2x-1=-14\end{cases}}\)

=> \(\orbr{\begin{cases}2x=15\\2x=-13\end{cases}}\)

=> \(\orbr{\begin{cases}x=\frac{15}{2}\\x=-\frac{13}{2}\end{cases}}\)

\(\left|-2x+3\right|-3=x\)

=> \(\left|-2x+3\right|=x+3\) (Đk: \(x+3\ge0\) => \(x\ge-3\))

=> \(\orbr{\begin{cases}-2x+3=x+3\\-2x+3=-x-3\end{cases}}\)

=> \(\orbr{\begin{cases}-3x=0\\-x=-6\end{cases}}\)

=> \(\orbr{\begin{cases}x=0\\x=6\end{cases}}\) (tm)

\(B=\frac{2}{15}+\frac{2}{35}+\frac{2}{63}+...+\frac{2}{399}\)

\(B=\frac{2}{3×5}+\frac{2}{5×7}+\frac{2}{7×9}+...+\frac{2}{19×21}\)

\(B=\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{19}-\frac{1}{21}\)

\(B=\frac{1}{3}-\frac{1}{21}\)

\(B=\frac{2}{7}\)

A=\(\frac{1}{3}\)+\(\frac{1}{6}\)+\(\frac{1}{10}\)+\(\frac{1}{15}\)+...+\(\frac{1}{66}\) 

A=\(\frac{1}{1\cdot3}\) +\(\frac{1}{2\cdot3}\) +\(\frac{1}{2\cdot5}\)+...+\(\frac{1}{6\cdot11}\)

A=\(\frac{1}{1}-\frac{1}{3}+\frac{1}{2}-\frac{1}{3}+\frac{1}{2}-\frac{1}{5}+...+\frac{1}{6}-\frac{1}{11}\)

A=\(\frac{1}{1}-\frac{1}{11}\)

=>A=\(\frac{10}{11}\)

B=\(\frac{2}{15}+\frac{2}{35}+\frac{2}{63}+...+\frac{2}{399}\) 

2B=\(\frac{1}{3\cdot5}+\frac{1}{5\cdot7}+\frac{1}{7\cdot9}+...+\frac{1}{19\cdot21}\)

2B=\(\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+...+\frac{1}{19}-\frac{1}{21}\)

2B=\(\frac{1}{3}-\frac{1}{21}\)

2B=\(\frac{2}{7}\)

B=\(\frac{2}{7}:2\)

=>B=\(\frac{1}{7}\)

Gọi số cần tìm là ab

Theo đề bài ta có ab9=13.ab

\(\Leftrightarrow\)ab.10+9=13.ab

\(\Leftrightarrow\)3ab=9

\(\Leftrightarrow\)ab=3???

Gọi số phải tìm là ab( a,b là số chữ số , a khác 0)

Ta có  9ab= 13 x ab

           900 +ab= 13 xab (cấu tạo số)

          12 x ab=900 (trừ cả 2 vế đi ab)

          ab= 900: 12

          ab=75

Vậy số phải tìm là 75.

Tet is a traditional holiday of our country Vietnam.
The season of Tet occurs around the biginning of February and end of Janaurỵ The meaning of Tet is ending old year and welcome a new year. Tet holiday is very special for Vietnamese families to reunite. At that time, all family members try to come back their homes and get together to prepare for Tet. Moreover they will buy new clothes and clean their house. A branch of Mai flower or a Kumquat tree can't be absent from every home. They bring a fresh atmosphere to the house. We decorate ancestral altar with a tray full of fruits and flowers.
Some typical Tet's food such as sweets, coconut jam, candied fruits, lemon seeds, rice cake , "thit kho"( stew pork with eggs). A special food can not absent is sky rice cake.. It is our country's traditional food on Tet holiday. Tet meal is more dilicious than our every day. 
On Tet holiday, people have many typical activities. Young persons takes part in the traditional games such as: tug; cooking rice, cock fighting, watching lion dance. Many people visit relatives to wish a happy new year. A dults will give lucky money for children. Woman going to pagoda to wish good things will come to their familỵ
In my oppinion, i cozy and fresh Tets atmosphere. All member of family talk together about a happy new year. I can hang out with my friend and don't worry about any thịng
" Tet" holiday is always in Vietnamese's heart.

The season of Tet occurs around the biginning of February and end of Janaurỵ The meaning of Tet is ending old year and welcome a new year. Tet holiday is very special for Vietnamese families to reunite. At that time, all family members try to come back their homes and get together to prepare for Tet. Moreover they will buy new clothes and clean their house. A branch of Mai flower or a Kumquat tree can't be absent from every home. They bring a fresh atmosphere to the house. We decorate ancestral altar with a tray full of fruits and flowers.
Some typical Tet's food such as sweets, coconut jam, candied fruits, lemon seeds, rice cake , "thit kho"( stew pork with eggs). A special food can not absent is sky rice cake.. It is our country's traditional food on Tet holiday. Tet meal is more dilicious than our every day. 
On Tet holiday, people have many typical activities. Young persons takes part in the traditional games such as: tug; cooking rice, cock fighting, watching lion dance. Many people visit relatives to wish a happy new year. A dults will give lucky money for children. Woman going to pagoda to wish good things will come to their familỵ
In my oppinion, i cozy and fresh Tets atmosphere. All member of family talk together about a happy new year. I can hang out with my friend and don't worry about any thịng
" Tet" holiday is always in Vietnamese's heart.The season of Tet occurs around the biginning of February and end of Janaurỵ The meaning of Tet is ending old year and welcome a new year. Tet holiday is very special for Vietnamese families to reunite. At that time, all family members try to come back their homes and get together to prepare for Tet. Moreover they will buy new clothes and clean their house. A branch of Mai flower or a Kumquat tree can't be absent from every home. They bring a fresh atmosphere to the house. We decorate ancestral altar with a tray full of fruits and flowers.
Some typical Tet's food such as sweets, coconut jam, candied fruits, lemon seeds, rice cake , "thit kho"( stew pork with eggs). A special food can not absent is sky rice cake.. It is our country's traditional food on Tet holiday. Tet meal is more dilicious than our every day. 
On Tet holiday, people have many typical activities. Young persons takes part in the traditional games such as: tug; cooking rice, cock fighting, watching lion dance. Many people visit relatives to wish a happy new year. A dults will give lucky money for children. Woman going to pagoda to wish good things will come to their familỵ
In my oppinion, i cozy and fresh Tets atmosphere. All member of family talk together about a happy new year. I can hang out with my friend and don't worry about any thịng
" Tet" holiday is always in Vietnamese's heart.The season of Tet occurs around the biginning of February and end of Janaurỵ The meaning of Tet is ending old year and welcome a new year. Tet holiday is very special for Vietnamese families to reunite. At that time, all family members try to come back their homes and get together to prepare for Tet. Moreover they will buy new clothes and clean their house. A branch of Mai flower or a Kumquat tree can't be absent from every home. They bring a fresh atmosphere to the house. We decorate ancestral altar with a tray full of fruits and flowers.
Some typical Tet's food such as sweets, coconut jam, candied fruits, lemon seeds, rice cake , "thit kho"( stew pork with eggs). A special food can not absent is sky rice cake.. It is our country's traditional food on Tet holiday. Tet meal is more dilicious than our every day. 
On Tet holiday, people have many typical activities. Young persons takes part in the traditional games such as: tug; cooking rice, cock fighting, watching lion dance. Many people visit relatives to wish a happy new year. A dults will give lucky money for children. Woman going to pagoda to wish good things will come to their familỵ
In my oppinion, i cozy and fresh Tets atmosphere. All member of family talk together about a happy new year. I can hang out with my friend and don't worry about any thịng
" Tet" holiday is always in Vietnamese's heart.

Tet holiday is coming with a lot of wishes and hopes! The old year is full of happiness and sadness, So I hope the next year is a happy new year! I think a happy year will begin with best wishes and lucky money from my grandfather, papa,mama,and my relatives! 
Tet is an opportunity for me to enrich my pocket preparing for many intention in the next year! In tet holiday, going out with friends, visiting teachers, relatives and especially eating ! the most happy time in the holiday is the last night of the old year when I and my sister stay with my grandfather, the time change from the old year to a new year is the time we receive best wishes from each others!
So happy!

A = 1 + 2 + 2² + 2³ + ... + 2⁵⁹ + 2⁶⁰

2A = 2 + 2² + 2³ + 2⁴ + ... + 2⁶⁰ + 2⁶¹

2A - A = 2⁶¹ - 1

B = 3 + 3² + 3³ + 3⁴ + ... + 3²⁰¹⁸ + 3²⁰¹⁹

3B = 3² + 3³ + 3⁴ + 3⁵ + ... + 3²⁰¹⁹ + 3²⁰²⁰

3B - B = 3²⁰²⁰ - 3

B = 3²⁰²⁰−32  

ta có 

\(A=2^0+2^1+2^2+...+2^{60}\)

\(\Rightarrow2A=2+2^2+2^3+...+2^{61}\)

\(\Rightarrow2A-A=2^{61}-1\)

\(\Rightarrow A=2^{61}-1\)

tương tự với biểu thức B bạn lấy 3B - B còn 2B rồi chia cho 2 sẽ ra \(\frac{3^{2020}-3}{2}\)

16 = ( x - 1 )⁴

2⁴ = ( x - 1 )⁴

2⁴ = ( 3 - 1 )⁴

=> x = 3

k chắc ! Cũng ms hk 

Sai bỏ qua . Thanks

                             16 = ( x - 1 )⁴

                                   2⁴ = ( x - 1 )⁴

                             ( x - 1 )⁴ = 2⁴

                         => x - 1 = 2 

                              x       = 2 + 1

                              x       = 3

                    Vậy x = 3

Bác tài chỉ việc đi thôi .  Còn chiếc xe thì để ở lại .

Vì câu hỏi nói : Vậy đố các bạn làmsao bác tài qua được cây cầu này (Không được bớt hàng ra khỏi xe)?

Hk tốt !!