\(\left[\frac{3}{\sqrt{a+2}}+\sqrt{a+2}\right]:\left[2+\frac{6}{\sqrt{a^4-4}}\right]\)

a) rút gọn biểu thức

b)Tính giá trị biểu thức P tại a=31-12\(\sqrt{5}\)

một người đi xe máy trong 20 phút được quãng đường 20km. vận tốc của người đó là bao nhiêu?

fill in the blanks with the appropriate form of the words in parentheses

smoking often ..........blood pressure/elevetion/

put the ..............part under a running cold tap /affect/

cover the burned area with a thick sterile ......../dress/

cool the burns immediately so as to........tissue damage/minimal/

điền từ thích hợp :

1. peter is very proud ...........his sister's studying result.

2. why are you so interested ...... playing computer games?

3. i am completely satisfied ......................my math result

4. there are many ways ......studying vocabulary

5. he goes to work .........foot because his house is near his office

viết câu tường thực:

1. " you can't park here" said the police officer to jack

2. " my trousers have to be ready this afternoon" said paul to the tailor

3. " you should work harder next school year, Nam " his mother said