1 вариант 1.Найдите корни уравнений: a) 17x² — 2x = 0. в) 441х2 = 256
Приложения:
Ответы
Объяснение:
17х² - 2х = 0
х(17х - 2) = 0
х1 = 0
17х - 2 = 0
17х = 2
х = 2 : 17
х2 = 2/17
Ответ: 0; 2/17
441х² = 256
х² = 256 : 441
х² = 256/441
х = ± 16/21
Ответ: -16/21; 16/21
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Read the text and for each question, choose the correct answer A, B, C or D.
Welcome to the Forbidden Island
The island of North Sentinel in the Andaman Islands of India has all the features of a tourist paradise, from white sandy beaches to lush green forests, However, this island's inhabitants aren't very welcoming to visitors, The people who live there are one of the last known tribes that have not made contact witn the outside world, and they attack anyone who tries to approach the island, There are around 250 Sentinelese living on the island, mostly in groups of around 30-40, and they live very simple lives. They are hunter-gatherers and live off the land and sea by hunting, fishing and collecting wild plants, There is no evidence that they farm and they don't seem to even know how to produce fire! They do, however, use simple tools like bows and spears, Scientists believe that the Sentinelese have lived on the island for approximately 60,000 years and since their language has no similarities with other tribes in the Andaman islands, it seems they have never had any significant contact with outsiders in all that time. This means that they are descendents of primitive stone-age tribes and this link to the past makes them very interesting to anthropologists, the scientists who study people and societies. It is very interesting, for example, to compare the Sentinelese with tribes from the other nearby Andaman Islands, who are generally living in modern society, For example, while the Sentinelese appear physically healthy and are thriving, some other Andaman tribes are on the verge of extinction, mainly due to contact with the outside world. This contact has resulted in widespread disease among tribes, and many of the areas where they lived have been destroyed by property developers from abroad. In fact, you could say that the Sentinelese's aggressive behaviour towards strangers has probably saved them from extinction. Fortunately, the Indian government has understood this, and tries not to interfere with the island or its natives. There is even a law that states that it is illegal to travel to the island, So, other than occasionally monitoring the island from far away, no contact has occurred in recent years, What the future holds for the Sentinelese people is uncertain, but for now their home remains the forbidden island.
1 What is the purpose of the text?
A to encourage people to visit an island
B to describe the daily life of a primitive tribe
C to explain the importance of protecting a tribe
D to complain about how people have treated a tribe
4 What does the author use to support his view that the tribe should not be contacted?
A their violent nature
B the fate of similar tribes
C their inability to communicate
D the poor treatment of the tribe in the past
2 What does the reader learn about the Sentinelese tribe from the text?
A They are skilled farmers.
B They are afraid of outsiders.
C They live in one large group.
5 What does the text say about the role of the Indian government in connection with the tribe? A It doesn't do enough to protect the tribe.
B It continues to try and contact the tribe.
C It is planning to develop the island.
D It prohibits contact with the tribe.
3 Why are the Sentinelese important to scientists?
A They use an undiscovered language.
B They aren't affected by deadly diseases.
C They are a connection to prehistoric man.
D They are the world's only un-contacted tribe.
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