Thực hiện phép nhân các phân thức sau:

a) a − 3 a + 1 . a 2 − 7 a − 8 a 2 − 5 a + 6  với a ≠ − 1 ; 2 ; 3 ;  

b) b 2 2 b 2 + 12 b + 18 . ( 4 b + 12 )  với  b≠−3.

21 hộp thừa 4 cái cốc

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 35 to 42.

        A mansion is a very large home. McDonald's is the name of a fast food hamburger chain. What do you get when you put the two together? You get McMansion, the recently created name for a type of large suburban, two storied home that originated in the United States. Many people love McMansions for their low price, abundant space and impressive styling, but the news is not all gooD. In fact, McMansions may now be a threatened species.

        McMansion became very popular in the United States during the 1990s, and this popularity continued for almost 20 years. During those years the economy was relatively strong, and banks were willing to lend large sums of money to people who wanted to buy a home. The result was an increase in the average home size. In 1988, the average new American home was 170 square meters, but by 2008 this had risen to 244 square meters, a 44% increase.

        To offset the greater costs of these large homes, land developers built many homes that all used a similar basic design and identical construction methods. Framing and interior fittings were constructed in

factories, instead of on site, and the materials used were often of a lower quality. Finally, the sections of land used for each house were much smaller than before.

        The result was suburban developments full of huge homes, often over 280 square meters in floor area, that all looked similar to each other. Their standardization and lowest possible-cost construction reminded people of McDonald's hamburgers, hence the term McMansion. For many people a McMansion was their dream home, but that dream is now rapidly turning sour.

        There are two main problems with McMansions. One problem is that their huge size means that they cost a lot to heat or cool. Energy is becoming more expensive, so owners are faced with huge bills if they try to heat or cool their home. The other problem is that McMansion owners are often in a lot of debt. They borrowed a lot of money to pay for their impressive home, but during the 2000s, with struggling economy and high unemployment, they couldn't afford to repay their loan.

        McMansion are still popular in some area, but no one is sure how long it will last. Will energy become even more expensive and force owners to downsize? Will the economy grow and banks become more willing to end again? Will the drop-in house prices allow larger, less affluent families to afford a McMansion? These questions are weighing heavily on the future of one of the most popular housing styles of the late 20th century.

(Source: Reading planet)

In paragraph 1, the writer introduces the concept of McMansion by _______.

A. comparing hamburgers and houses

B. introducing various types of homes in the United States

C. discussing the advantages and disadvantages of McMansions

D. explaining how McMansions were named

từ 1->9 có tất cả:{9-1}:1+1=9 chữ số

từ 10->99 có tất cả:{99-10}:1nhân2=180 chữ số

từ 100->152 có tất cả:{152-100+1} nhân 3=159 chữ số

vậy có tất cả:9+180+159=348 chữ số

làm tròn thành 6,7% nha bạn, cần cách giải không

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 33 to 40.

Early peoples had no need of engineering works to supply their water. Hunters and nomads camped near natural sources of fresh water, and populations were so sparse that pollution of the water supply was not a serious problem. After community life developed and agricultural villages became urban centers, the problem of supplying water became important for inhabitants of a city, as well as for irrigation of the farms surrounding the city. Irrigation works were known in prehistoric times, and before 2000 BC the rulers of Babylonia and Egypt constructed systems of dams and canals to impound the flood waters of the Euphrates and Nile rivers, controlling floods and providing irrigation water throughout the dry season. Such irrigation canals also supplied water for domestic purposes. The first people to consider the sanitation of their water supply were the ancient Romans, who constructed a vast system of aqueducts to bring the clean waters of the Apennine Mountains into the city and built basins and filters along these mains to ensure the clarity of the water. The construction of such extensive water-supply systems declined when the Roman Empire disintegrated, and for several centuries local springs and wells formed the main source of domestic and industrial water.

The invention of the force pump in England in the middle of the 16th century greatly extended the possibilities of development of water-supply systems. In London, the first pumping waterworks was completed in 1562; it pumped river water to a reservoir about 37 m above the level of the River Thames and from the reservoir the water was distributed by gravity, through lead pipes, to buildings in the vicinity. Increased per-capita demand has coincided with water shortages in many countries. Southeast England, for example, receives only 14 per cent of Britain's rainfall, has30 per cent of its population, and has experienced declining winter rainfall since the 1980s.

In recent years a great deal of interest has been shown in the conversion of seawater to fresh water to provide drinking water for very dry areas, such as the Middle East. Several different processes, including distillation, electrodialysis, reverse osmosis, and direct-freeze evaporation, have been developed for this purpose. Some of these processes have been used in large facilities in the United States. Although these processes are successful, the cost of treating seawater is much higher than that for treating fresh water.

From A. Briggs’ article on culture, Microsoft® Student 200

The word “disintegrated” in paragraph 1 is closet in meaning to ______.

A. emerged

B. failed

C. distorted 

D. thrived