Между какими целыми числами заключено значение выражений?:

1) \sqrt{0,9}

2) \sqrt[3]{9}

3) \sqrt[4]{21,5}

4) \sqrt[5]{1000}

На сколько градусов надо изобарно нагреть газ, чтобы он занял объем, вдвое больший по сравнению с объемом при 0*С?

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Most of the western nations have the same basic environmental problems, but they take different forms in each country. Here you can read about some of the dangers facing Britain’s environments.

One of Britain’s environmental successes has been the control of air pollution, especially in London. Thirty years ago hundreds of people died every year from the dreadful London smogs. Since then London and many other cities have become smokeless zones, areas where no coal fires are allowed. But now the increase in traffic is threatening serious air pollution in our cities again.

However, the commonest air pollution comes from the cigarette smoke which pollutes many public places, like cinemas, pubs and restaurants. Though cigarette advertisements are not allowed  on TV or radio, you can still see them on posters in cinemas and in newspapers and magazines. The advertisements don’t tell you that doctors believe cigarettes cause 30.000 deaths in Britain every year.

Traffic and aircraft can cause serious noise pollution. Air-crafts are very noisy when they take off and the noise spreads over a wide area. Heathrow airport, near London, is the busiest airport in the world. Planes are only allowed to take off and land at Heathrow between six in the morning and eleven at night, but during the day fifty planes take off and land there every hour. 

Решите задачу: 48 км против течения реки катер проплывает на 48 мин дольше, чем 56 км по течению реки. Найдите скорость течения реки, если собственная скорость катера 12 км/ч. 

с решением пожалуйста!))))))))