1 комбайн убирает поле за x час, а за 1 час убирает 1/x часть поля,
2 комбайн убирает поле за y час, а за 1 час убирает 1/y часть поля,
А вместе они убирают поле за 20 час, а за 1 час 1/20 часть поля
1/x + 1/y = 1/20
1/2 участка 1 комбайн уберет за x/2 час, а 1/3 участка 2 комбайн за y/3 час.
x/2 = y/3 + 3
Получили систему
{ 20y + 20x = xy
{ x = 2(y + 9)/3
Подставляем
20y + 40(y + 9)/3 = 2y(y + 9)/3
60y + 40y + 360 = 2y^2 + 18y
2y^2 - 82y - 360 = 0
y^2 - 41y - 180 = 0
D = 41^2 + 4*180 = 2401 = 49^2
y1 = (41 - 49)/2 < 0
y2 = (41 + 49)/2 = 45
x = 2(45 + 9)/3 = 2*54/3 = 2*18 = 36
1 комбайну нужно 36 часов, а 2 комбайну 45 часов
Пошаговое объяснение:
Everyone has different opinions. Some people think friends are more important than family. Others think family is more important than friends. I believe that family is more important than friends. Family is very important for every person! Relatives will always support in difficult times, lend a helping hand. The family has its own atmosphere. Their customs, laws. Family is the people close to you who love you and whom you love. Family is the most precious thing we have! But, on the other hand, friends are important, because without them our life would be boring and uninteresting, we could share with them secrets, outlook on life. Most people think family is more important than friends. Since you are forever with your family, she will not leave you, but friends come and go.Family is more important to me, because family is the most precious thing we have!
Пошаговое объяснение:
