53 Are there 800 pupils in you school?

53 There are 6 children in your family

55 How much do a cack and an orange cost?

57 How much does a bottle of cooking oil cost

59 My father is going to Ha Noi by car 

60 Nam's father has a white car

61 How much beef would you like

63 I go to school by bicycle everyday

65 Phong's sister is nhung

67 Trung is Mr Minh's son

68 Huyen goes to school on foot...

69Nam is Phuong's brother

cảm ơn bạn ạ

I'm going to visit Mui Ne this summer.

I'm going to visit Mui Ne this summer

help j?/

ảnh bị lỗi nhé

c.

ĐKXĐ: \(sinx\ne0\Rightarrow x\ne k\pi\)

\(1-\dfrac{\sqrt{3}cosx}{sinx}-4cosx=0\)

\(\Rightarrow sinx-\sqrt{3}cosx-4sinx.cosx=0\)

\(\Leftrightarrow sinx-\sqrt{3}cosx=2sin2x\)

\(\Leftrightarrow\dfrac{1}{2}sinx-\dfrac{\sqrt{3}}{2}cosx=sin2x\)

\(\Leftrightarrow sin2x=sin\left(x-\dfrac{\pi}{3}\right)\)

\(\Leftrightarrow\left[{}\begin{matrix}2x=x-\dfrac{\pi}{3}+k2\pi\\2x=\dfrac{4\pi}{3}-x+k2\pi\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{\pi}{3}+k2\pi\\x=\dfrac{4\pi}{9}+\dfrac{k2\pi}{3}\end{matrix}\right.\)

a.

\(\Leftrightarrow3sin3x-4sin^34x-\sqrt{3}cos9x=2sin2x\)

\(\Leftrightarrow sin9x-\sqrt{3}cos9x=2sin2x\)

\(\Leftrightarrow\dfrac{1}{2}sin9x-\dfrac{\sqrt{3}}{2}cos9x=sin2x\)

\(\Leftrightarrow sin\left(9x-\dfrac{\pi}{3}\right)=sin2x\)

\(\Leftrightarrow\left[{}\begin{matrix}9x-\dfrac{\pi}{3}=2x+k2\pi\\9x-\dfrac{\pi}{3}=\pi-2x+k2\pi\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{\pi}{21}+\dfrac{k2\pi}{7}\\x=\dfrac{4\pi}{33}+\dfrac{k2\pi}{11}\end{matrix}\right.\)

Help mik đi mik tick cho

\(\dfrac{2}{7}=\dfrac{10}{35}=\dfrac{12}{42}=\dfrac{16}{56}\)

đề :)?

k hiểu sao e cập nhật liên tục ròi mà vẫn khongg đc :((

2.A

3.A