Tính  C = 1 − 1 5 . 1 − 2 5 1 − 3 5 ... 1 − 9 5

Tính nhanh:

a)  4 7 + 3 4 + 2 7 + 5 4 + 1 7

b)  − 5 7 + 3 4 + − 1 5 + − 2 7 + 1 4

Chứng tỏ hai phân thức 4 x 2 − 4 xy + y 2 y 3 − 6 y 2 x + 12 yx 2 − 8 x 3  và   − 1 2 x − y với y≠2x bằng nhau.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 1 to 7.

One of the highest honors for formalists, writers, and musical composers is the Pulitzer Prize. First awarded in 1927, the Pulitzer Prize has been won by Ernest Hemingway, Harper Lee, John F. Kennedy, and Rodgers and Hammerstein, among others. As with many famous awards, this prize was named after its founder, Joseph Pulitzer.

Joseph Pulitzer’s story, like that of many immigrants to the United States, is one of hardship, hard work and triumph. Born in Hungary, Joseph Pulitzer moved to United States in 1864. He wanted to be a reporter, but he started his American life by fighting in the American Civil War. After the war, Pulitzer worked for the German - language newspaper, the Westliche Post. His skills as a reporter were wonderful, and he soon became a partial owner of the paper.

In 1978, Pulitzer was able to start a newspaper of his own. Right from the first edition, the newspaper took a controversial approach to new. Pulitzer wanted to appeal to the average reader, so he produced exciting stories of scandal and intrigue. Such an approach is commonplace today, but in Pulitzer’s time it was new and different. The approach led to the discovery of many instances of corruption by influential people. Pulitzer ‘paper became very famous and is still produced today.

The success of Joseph Pulitzer’s newspaper made him a very wealthy man, so he wanted to give something back to his profession. Throughout his later years, he worked to establish university programs for the teaching of journalism, and he funded numerous scholarships to assist journalism students. Finally, he wanted to leave a legacy that would encourage writers to remember the importance of quality. On his death, he gave two million dollars to Columbia University so they could award prizes to great writers.

The Pulitzer Prize recipients are a very select group. For most, winning a Pulitzer Prize is the highlight of their career. If an author, journalist, or composer you know has won a Pulitzer Prize, you can be sure they are at the top of their profession.

Which sentence about Joseph Pulitzer is true according to the reading passage? 

A. He received a scholarship when he was a university student.

B. He was rich even when he was young

C. He was a reporter during the American Civil War

D. He immigrated to the United States from Hungary

Điền chữ số vào dấu * để: 

a) 423 * chia hết cho 3 và 5 .

b) 613 * chia hết cho 2 và 9.

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42.

     A rather surprising geographical feature of Antarctica is that a huge freshwater, one of the world's largest and deepest, lies hidden there under four kilometers of ice. Now known as Lake Vostok, this huge body of water is located under the ice block that comprises Antarctica. The lake is able to exist in its unfrozen state beneath this block of ice because its waters are warned by geothermal heat from the earth's core. This thick glacier above Lake Vostok actually insulates it from frigid temperatures (the lowest ever recorded on Earth) on the surface.

     The lake was first discovered in the 1970s while a research team was conducting an aerial survey of the area. Radio waves from the survey equipment penetrated the ice and revealed a body of water of indeterminate size. It was not until much more recently that data collected by satellite made scientists aware of the tremendous size of the lake; satellite-borne radar detected an extremely flat region where the ice remains level because it is floating on the water of the lake.

     The discovery of such a huge fresh water lake trapped under Antarctica is of interest to the scientific community because of the potential that the lake contains ancient microbes that have survived for thousands upon thousands of years, unaffected by factors such as nuclear fallout and elevated ultraviolet light that have affected organisms in more exposed areas. The downside of the discovery, however, lies in the difficulty of conducting research on the lake in such a harsh climate and in the problems associated with obtaining uncontaminated samples from the lake without actually exposing the lake to contamination. Scientists are looking for possible ways to accomplish this.

Which of the following is closest in meaning to "frigid" in the first paragraph?

A. extremely cold

B. never changing

C. quite harsh 

D. rarely recorded