chọn sai môn học rồi nha

1. B
2. A

\(7^{2021}+7^{2020}-7^{2019}=7^{2019}.7^2+7^1.7^{2020}-7^{2019}.1\)

\(=7^{2019}\left(7^2+7-1\right)=7^{2019}\left(49+7-1\right)=7^{2019}.55\)

Mà \(55⋮11\Leftrightarrow7^{2019}.55⋮11\)

Vậy \(7^{2021}+7^{2020}-7^{2019}⋮11\)

em ko biết em mới học lơp3thui

4*cos(pi/6-a)*sin(pi/3-a)

=4*(cospi/6*cosa+sinpi/6*sina)*(sinpi/3*cosa-sina*cospi/3)

=4*(căn 3/2*cosa+1/2*sina)*(căn 3/2*cosa-1/2*sina)

=4*(3/4*cos^2a-1/4*sin^2a)

=3cos^2a-sin^2a

=3(1-sin^2a)-sin^2a

=3-4sin^2a

=>m=3; n=-4

m^2-n^2=-7

Ta có:

\(\dfrac{1}{cos^2x-sin^2x}+\dfrac{2tanx}{1-tan^2x}=\dfrac{1}{cos2x}+tan2x=\dfrac{1}{cos2x}+\dfrac{sin2x}{cos2x}=\dfrac{1+sin2x}{cos2x}=\dfrac{cos2x}{1-sin2x}\)

\(\Rightarrow P=a+b=2+1=3\)

My taste in art is not the same as my sister's

I think romantic films aren't as interesting as action films

I don't speak Japanese and my new friend doesn't, either

Nester goes climbing less than before

He's had a cold for 2 days because he didn't wear enough clothes

I will spend an hour gettign this task done

My father prefers tea to coffee

Eat less or you will be obese

1 B. other (forms ở số nhiều $\rightarrow$ other forms)

2 D. important (đứng trước danh từ form, chọn tính từ hợp nghĩa)

3 A. sung (cấu trúc bị động đi kèm composed and sung)

4 A. ago (hundreds of years ago - hàng trăm năm trước)

5 C. who (mệnh đề quan hệ chỉ người who originally composed them)

6 C. instruments (nhạc cụ: flute, accordion, etc.)

7 D. also (được gọi là... cũng được gọi là...)

8 A. bad (protest songs phàn nàn về những điều tồi tệ: bad things)

1 He didn't remember anything about the event, and neither did she. (Hoặc: He didn't remember anything about the event, and she didn't either.)

2 She doesn't sing as beautifully as her sister.

3 I think no students in the class are cleverer than Nick. (Hoặc: I think no students in the class are as clever as Nick.)

4 I go to the same school as my cousin.

5 My friend will never have such a chance again, and neither will I. (Hoặc: My friend will not have such a chance again, and I won't either.)

6 For me, an ape isn't different from a monkey.

7 Jack doesn't sleep as much as he should.

8 By using public transport more, we can reduce air pollution.

9 Her father has been working as a television reporter since she was born. (Hoặc: Her father has been a television reporter since she was born.)

10 Last year he worked harder and more carefully than he does this year.

Thứ tự sắp xếp: 3 – 2 – 4 – 1 – 6 – 5

1 A. Music In Life

2 D. Music has made people's life less entertaining

3 B. it makes us calm in our daily life

4 C. unanswered

5 C. Music has long been a wonderful way for man to enjoy life and understand each other.