Запишите математическую модель данных ситуаций, если a - масса арбуза, b-масса дыни:

а) Масса одного арбуза и двух дынь равна 37 кг;

б)Масса трех арбузов тяжелее дыни на 17 кг;

в)масса двух арбузов больше 21 кг;

г) масса трех дынь меньше 30 кг.

In our days a lot of people are fond of a variety of sports both amateur and professional. But some people think that sport is useless, I think they are absolutely stupid.

In my opinion, all people should do sports because sport is health. Sport makes you stronger faster, fitter, more beautiful and gives a lot of useful features, both physical and moral. Besides, sports can cure you of most diseases. Take for example swimming, if a child with childhood are present at a back problem, many doctors recommend swimming as it really helps to get rid of back problems. Or if vision problems, doctors recommend playing tennis.

Nevertheless, some sports are very dangerous, and they are likely to get injured after which there can be complications with his health. Also, some teens are engaged in professional sports. And so they have not enough time to study, because of this they have bad grades.

However, I disagree with this opinion because in a dangerous sport you have special equipment that protects you and skilled trainers who looked after all your actions. Of course, there is not enough time for studying but there are special sports schools with a flexible schedule that depends of your trainings.

To sum up, I want to say that a sport is very helpful for all people, if you want to be healthy and strong to stand up for your life you must do sports.