1.cho x, y, z là 3 số thực dương thỏa mãn x+y+z=2. tìm giá trị biểu thức

M = \(\dfrac{x^2}{y+z}+\dfrac{y^2}{x+z}+\dfrac{z^2}{x+y}\)

2. cho a, b, c >0 và a+b+c = 3

Cm: \(\dfrac{a+1}{b^2+1}+\dfrac{b+1}{c^2+1}+\dfrac{c+1}{a^2+1}\) \(\ge3\)

cho a,b,c>0 và a+b+c = 3 cm:

\(\dfrac{a+1}{b^2+1}+\dfrac{b+1}{c^2+1}+\dfrac{c+1}{a^2+1}\) \(\ge3\)

1.CM: với mọi số nguyên n thì \(n^3+2013n^2+2n\) chia hết cho 6

2. tìm tất cả các số tự nhiên sao cho A= \(n^2+10n+136\) là số chính phương

1. The doctor advised me (not stay) .......... uplate

2. It's no good (read)........ this article

3. When I (go)........for a walk, it (rain)...

1 We are all impressed by their............(friend).

2. According to the ...., the english lesson starts at ten (time)

3. my teacher usually ..... me to learn harder(courage)

4. Nga hpoes to speak english as.... as her teacher(good)

5. I can't sit on the chair. It is .......(comfort)

a. Tìm x thỏa mãn \(\sqrt{x^2-2x+25}-\sqrt{x^2-2x+9}=2\)

Tính giá trị biểu thức \(\sqrt{x^2-2x+25}+\sqrt{x^2-2x+9}\)

b. Tìm số tự nhiên n để \(\sqrt{n^2+91}\) là số tự nhiên

1. they often grow rice but they (do) maize this year

2. by the end of the year, my parents (be) married for nearly twenty years

3. up to now we (lose) more than two hundred species of rare plants and animals

4. how many pieces of music Mozart (compose) before he died?

5. why you always (complain)? I can't stand your bad temper

6.I am sorry for what i (do)

Mối quan hệ giữa VN- Mỹ từ 1945 đến nay

Tag question (câu hỏi đuôi)

1. Today is not Monday, ........?

2. I spent three hours doing my homework,...... ?

3. Your bike is stolen,......?

4. Tomorrow will be Saturday,.....?

5. I've no idea for it,...?

6. Andrew has not got many friends,...?