Trên mái thì đen, ở dưới thì xanh đen

Cho hai số thực dương a, b thỏa mãn 9 a 3 + a b + 1 = 3 b + 2 . Giá trị lớn nhất của biểu thức S = 6a - b là

A.  17 12

B.  82 3

C.  11 3

D.  89 12

Vì bà đi tàu ngầm

Let’s ________ (6) at this picture. It’s the Great Pyramid of Giza. It __________ (7) a symbol of Egypt and the last of the ancient Seven Wonders of the World. It is located on the Giza, near the modern city of Cairo. It is __________ (8) and the oldest one among the three pyramids of the Giza Pyramid Complex. Scientists believe that this pyramid was built ___________ (9) a period of 10 to 20 years. For over 3,800 years, the Great Pyramid of Giza stood tall as the world’s tallest structure. In the pyramid, there is the _________ (10) of Khufu, the Fourth Dynasty Egyptian pharaoh.

Question 7:

A. are      

B. were      

C. have been      

D. is

To xem nham de bai de bai sai

A=2^100-2^99+2^98-2^97+..+2^2-2

=>2A=2^101-2^100+2^99-2^98+...+2^3-2^2

=>2A+A=(2^101-2^100+2^99-2^98+..+2^3-2^2)+(2^100-2^99+2^98-2^97+..+2^2-2)

=>3A=2^101-2

=>A=(2^101-2)/3