Cho (O) bán kính 3 cm Một điểm S sao cho OS=5cm Vẽ tiếp tuyeems SA với đtron (O)

a,Tính SA?Góc SOA?

b,Qua A vẽ đường thẳng vuồng góc với OS tại I cắt đtron (O) tại B.CM SB là tiếp tuyến của (O)

Cho đtron (O) đường kính AB.Ax và By là 2 tiếp tuyến đtron (O) trên Ax lấy điểm C trên By lấy điểm D sao cho góc COD=90 độ Gọi N là giao điểm của CO và By

a, CM: tam giác CDN cân

b,CD là tiếp tuyến của đtron (O)

NLXH:"Những niềm vui ngọt ngào nhất trong cuộc sống chỉ đến khi các em nhận ra rằng mình không có gì đặc biệt"Hãy viết bài văn

CÂU BỊ ĐỘNG

1.They can make tea with boiled water. 

-> Tea ...................................................................

2. He is instructing all the workers of the plan at the moment.

-> All the workers of the plan ...................................................................

3. A boy has just taken some of my books away. 

-> Some of my books ...................................................................

4. They will hold the celebration before January.

-> The celebration ...................................................................

5. They have to repair their car.

-> Their car ...................................................................

6. The boys broke the window last night.

-> The window ...................................................................

7. People spend much money on advertising everyday.

-> Much money ..................................................................

8. Hung took some pictures of his father away yesterday.

-> Some pictures of his father .........................................................

9. They may use their rooms for the classrooms.

-> Their rooms ..................................................................

10. The teacher is going to punish some students.

-> Some students ...................................................................

CÂU BỊ ĐỘNG

1. We must pay the bill at once.

-> The bill ………………………………………………………………

2. I will repair your bicycle tomorrow afternoon.

-> Your bicycle………………………………………………………………

3. Penicillin can cure many dangerous diseases.

-> Many.. ……………………………………………………………………

4. Does your country export rice to Britain?

-> Is rice ……………………………………………………………………

5. Clement Clarke Moore wrote the poem in 1823.

-> The poem ………………………………………………………………

6. Christmas cards should be sent a week before Christmas day.

-> You ………………………………………………………………………

7. Nobody has used this machine for year.

-> This machine ..…………………………………………………………

8. They use recycled plastic to make toys and utensils.

 -> Recycled………………………………………………………………..

9. Tax free goods can be bought before you get on the plane.

-> You ……………………………………………………………………

10. The repairman is going to repair my car next week.

-> We are going to have……………………………………………………

Giai hptr

a,\(\left\{{}\begin{matrix}3x+y=4\\4x-3y=14\end{matrix}\right.\)

b,\(\left\{{}\begin{matrix}5x-3y=7\\4x+5y=13\end{matrix}\right.\)

Giai hệ ptr

\(\left\{{}\begin{matrix}\dfrac{1}{x}+\dfrac{3}{y}=\dfrac{2}{3}\\\dfrac{4}{x}-\dfrac{5}{y}=\dfrac{2}{7}\end{matrix}\right.\)

Tìm m để đt(3m-1)x+y=m-2 đi qua 2 đt

\(\left\{{}\begin{matrix}3x+2y=5\\4x-3y=1\end{matrix}\right.\)