Ответ по предмету Математика: определите, каким условиям должны удовлетворять числа a и b, что бы выполнялось равенство a:b=b:a

Предмет: Химия, автор: islamyuldashev2911

У якій сполуці вміст Оксигену більший ( за масовою часткою) у натрієвій нітрату(NaNo3 чи гідроген пероксиді (N2 O2)??? Срочно будь ласка!!!

6 лет назад

Предмет: Математика, автор: milki0000

мне нужно срочно это решить

6 лет назад

Предмет: Английский язык, автор: victoriaschiryaeva

Помогите пожалуйста. Сделайте пересказ 16 предложений.
Everybody admits that nowadays the world faces a number of serious problems connected with the environment. Among the environmental problems threatening living things and humans the first place is probably taken by pollution.
One of its forms is air pollution. All burning produces smoke, soot and gases which may be harmful. Burning petrol also produces metal called lead. Lead is poisonous. You can breathe it in, you can take it in through food and water and it stays inside slowly poisoning you.
Air pollution also results in acid rains. Our power stations burn coal or oil. Their burning produces poisonous gases. The wind carries them high into the sky. There they come together with water in the air and make acid rain, acid fog and acid snow, which fall onto the ground and poison rivers and lakes. Trees suffer from acid rain no less than water plants and animals. Millions of trees have died in Canada and northern Europe because of acid rain. The acid eats into the stone destroying buildings. Many of the world’s oldest and most beautiful buildings are in danger now.
Water pollution is as dangerous as air pollution. People dump too much waste into seas, lakes and rivers. As a result they cannot clean themselves. The sea washes the waste onto the beaches and coasts and pollutes them. The worst kind of sea pollution is an oil spill. Oil contains poisonous chemicals. If oil is spilt at sea, air can’t get to the plants and animals under the water and they die. So do waterbirds which get into oil spills.
Dumping industrial and domestic waste leads to soil pollution. Some of this waste may be radioactive and cause nuclear pollution, extremely dangerous to people and animals. Nuclear power stations producing electricity are supposed to be “environmentally friendly”. But if something happens to such a station or something goes wrong there, it begins to pollute vast areas and the result is usually terrible. Such accidents happened in Britain, the USA, Japan and Chernobyl, Ukraine. Used nuclear fuel is very toxic. People tend to keep it under water or bury it deep under the ground in special containers. But we should remember that radioactive waste remains radioactive and dangerous for thousands of years.
One more problem that is being widely discussed is global warming, or greenhouse effect. The gases and soot in the atmosphere make a kind of “screen” which doesn’t allow heat get back into space. There is a danger that the temperature can rise by some degrees in the near future. Climatic changes may do a lot of harm to our planet and those who populate it.
The list of environmental problems also includes growth of population, shortage of food and fresh water in some parts of the world, destruction of wildlife and many others. A lot of them are man-made. Time has come for us to learn to live in harmony with nature and save our planet.

6 лет назад

Предмет: Математика, автор: Rotlakk

Найдите sin(7π2−α), если sinα=0,8 и α∈(π2;π).

9 лет назад

Предмет: Математика, автор: daryfastex

В треугольнике abc ac=bc c=136 найдите внешний угол CBS

9 лет назад

определите, каким условиям должны удовлетворять числа a и b, что бы выполнялось равенство a:b=b:a

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