giải phương trình

\(3\sqrt{x-2}\)-\(\sqrt{4x-8}\)+4.\(\sqrt{\dfrac{9x-18}{4}}\)=14

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer.

1.    I remember Alice as a spotty girl but she's turned _________ a beautiful woman.

          a. to                            b. in                          c. into                         d. on

2.    Stephen always wanted to be an actor when he  _________ up.

          a. came                      b. grew                    c. brought                 d. settled

3.    They've  _________ a new tower where that old building used to be.

          a. put up                    b. put down            c. pushed up             d. pushed down

4.    It's high time Bill got a steady job and  _________ He's almost thirty.

          a. settled in               b. settled down     c. turned in               d. turned down

5.    The plane _________ down the minutes late because of bad weather.

          a. put                          b. flew                     c. landed                   d. touched

6.    He kept his marriage a secret for years, but eventually the truth _________

          a. went in                  b. went off              c. came out               d. came through

cho biểu thức

P=\(\left(\dfrac{1}{\sqrt{x}-x}+\dfrac{1}{1-\sqrt{x}}\right)\):\(\dfrac{\sqrt{x}+1}{\left(1-\sqrt{x}\right)^2}\)

a) tìm đk và rút gọn

b) Tìm x để P>0

CHỨNG MINH RẰNG 

P=\(\left(\dfrac{\sqrt{x}}{\sqrt{x}+3}+\dfrac{3}{\sqrt{x}-3}\right)\)x\(\dfrac{\sqrt{x}+3}{x+9}\)=\(\dfrac{1}{\sqrt{x}-3}\) với x\(\ge\)0 và x\(\ne\)9

Thuộc địa là gì?

Chứng minh rằng

cosA + cosB + cosC \(\le\dfrac{3}{2}\)