Bài 2: 

1: \(=\dfrac{-6}{12}+\dfrac{-4}{12}+\dfrac{15}{12}=\dfrac{15-4-6}{12}=\dfrac{5}{12}\)

2: \(=\dfrac{10-4-7}{8}=\dfrac{-1}{8}\)

3: \(=\dfrac{2}{10}-\dfrac{5}{10}+\dfrac{9}{10}=\dfrac{6}{10}=\dfrac{3}{5}\)

4: \(=\dfrac{15}{12}-\dfrac{4}{12}+\dfrac{14}{12}=\dfrac{25}{12}\)

=\(\left(2-1\right)\left(2+1\right)\left(2^2-1\right)....\left(2^{20}-1\right)\) +1

=\(\left(2^2-1\right)\left(2^2+1\right)\left(2^4+1\right)....\left(2^{20}+1\right)+1\)

=\(\left(2^4-1\right)\left(2^4+1\right)....\left(2^{20}+1\right)+1\)

=.....

=\(\left(2^{20}-1\right)\left(2^{20}+1\right)+1\)

=\(2^{40}-1+1\)

=\(2^{40}\)

Chuc ban hoc tot

Sai rồi, nếu mũ là 32 thì bài này làm thế đc chứ mũ 20 thì ko làm như này được

1. số thứ 234 của số có 3 chữ số là số 333

3. số thứ 234 của số có 3 chữ số là số 1233

1. Lan can be helped by Nam

2. Lan and Hoa will be helped by Nam

3. We should be helped by Nam

1. Lan can be helped

2. Lan and Hoa will be helped

3. We should be helped

1. We must be helped

2. We used to be helped 

3. Lan has to helped 

1.      Nam must help us.                                                                    →………We must be helped…………………………………………

2.      Nam used to help us.                                                                         →……We used to be helped ……………………………………………

3.      Nam has to help Lan.                                                         →………… Lan has to helped………………………………………

BẠN GÕ RA ĐI MÌNH NHÌN HƠI KHÓ

GÕ A MÁY TÍNH Ý ĐỪNG VIẾT

Câu 1: \(B.\frac{5}{8}\)

Câu 2: \(C.x=20;y=12\)

Câu 3: \(B.\frac{1}{4}\)

1.=> You’ll be helped by his father tomorrow.

2. => This bottle was broken by Peter.

3.=> Letters are typed in the office by Mary.

4. => English is being learnt in the room.

1. His father will help you tomorrow.

\(\rightarrow\) You will be helped by his father tomorrow

2. Peter broke this bottle.

\(\rightarrow\) This bottle were broken by Peter

3. Mary types letters in the office.

\(\rightarrow\) Letters are typed in the office by Mary

4. They are learning English in the room.

 \(\rightarrow\) English is being learned in the room by them

5.Steven has forgotten the book.

\(\rightarrow\) The book has been forgotten by Steven

You will be helped by his father tomorrow

This bottle was broken by Peter 

Letters are typed by Mary in the office

English is being learned in the room

The book has been forgotten by Steven