Cho tam giác ABC vuông tại A đường tròn tâm O đường kính AB cắt các đoạn BC và OC lần lượt tại D và I . . Gọi H là hình chiếu của A lên OC ; AH cắt BC tại M . Chứng minh MD.BC=MB.CD

Cho phương trình : x² -(m+2)x -m-3 =0 (1)

a) Giải phương trình khi m=1

b) Tìm m để phương trình (1) có hai nghiệm x₁ ,x₂ thỏa mãn x_1² +x_2² >1

1. the parents thanked the women ... had saved their son ( which , that , whose , whom,...)

2. two men , neither of ... i had seen before , came into my office

3. he ate the food ... noone else wanted

4. john has got a new mobile phone ... take a photo

5. the village... i ran out of petrol didn't have a petrol station

6. the job for .... she has applied is in london

7. john sold his computer , ... he no longer needed , to his cousin

8. teddy hs two car , one of .... is very expensive

II .

1. a scientist has won the nobel prize . he discovered a new planet -> a sicientist....

2. bananas are exported to europe -> people ...

3. " do these clothes belong to you ?" said liz to me -> liz asked ...

III.

1. she looked frightered as if she (see) a ghost .

2. i couldn't resist (laugh) at the way he answered my question .

3. all the tickets (sell) out by the time we arrived at the theater .

4. it was one of the happiest evenings i (spend).

Hòa tan 4g hỗn hợp 2 muối K2CO3 và NaCl thu được 0.448 lít khí ( đktc).

a. Viết phương trình pư

b. Tính CM HCl đã dủng

c. Tính thành phần % về khối lượng của mỗi muối trong hỗn hợp ban đầu .

1. It / be / long time / since / i / last / hear / you .

2. You /like / come / stay / me / cottage / countryside ?

3. You / your family / welcome/ if / want / visit / us.

4. What / about / come / the end / next month ?

5. Write / let / me / know / if / come .

6. We want to buy ... that will save money ( produce)

7. Mary sent me a letter . It was funny.

8. Many people speak German .they live in australia

7a.M

Cho tam giác ABC AB=12 ,AC =16, BC=20. Đường cao AH . Từ 1 điểm D thuộc AB kẻ đường thẳng song song BC cắt AC tại E . Tìm vị trí của D để BD + EC = DE

Cho 2.7 g Al tác dụng với 100ml dung dịch HCl 6M . Tính thể tích khí thoát ra ở đktc.

b) Cần bao nhiêu gam NaOH để trung hòa lượng chất dư ở phản ứng trên .

1. If you fell like ( stay ) with us , just send us fax .

2. He wishes that he ( work ) harder , but it is too late now

3. If he improves his spelling , he will get good grades -> unless...

4. I will be back tomorrow " he said -> he said...

5. I miss you , so phoned you quite often . -> because ọf...

6. They haven't phoned us for a month -> it has been ...

7. We have never been to Viet 's native lang -> this is ...

8. Do these clothes belong to you ? " said Luz to me -> Luz asked ...

9. They / play/ well / yesterday/ however / lose / the match .

10. You/ could / tell me / what time / the concert start ?

11. Christmas / one / biggest / festival / the year / Britain.

1. "I don't understand what you are saying " Tom told us.-> tom told us thàt...

2." There isn't any information about these colleges " Nam said -> Nam said...

3. Please call me ai 6 oclock tomorrow morning -> Mai told...

4. You must come today -> Hoa told me that ..

1.Mr Paker feeds the chicken. He collects their eggs.

> Mr Paker not only feeds...

2. The food was too bad for the children to eat > the food was so ...

3. The guide warned... ( not us , us not to, us not , to us not ) touch these wires because it could be dangerous.

4. I wish people ...( will drive ,would drive,drove,drive) more slowly , then there would be fewer accidents .

5. Five gold medals have ...( won, be won , being won,been won) by english simmers.

6. They felt tired and hungry,so they ( sit) down under a tree and rested for lunch.

7. She is having an exami nation . She wishes she ( spen) a day off on a farm now.