Решите Уравнение корень из 18 - 2корня из 6 + корень из 24 - 4корня из 2

Кусок стекла имеет форму квадрата . Когда от него отрезали полосу шириной 20см ,его площадь стала равной 3500см^2 . Найдите первоначальные размеры куска стекла.

Change into passive. 

1. They must visit Mr. Grey in the morning.
2. He will speak to his cousin tomorrow.
3. They often give her fruits from their garden.
4. They built a new hospital last year.
5. She is reading a book at the moment.
6. When Jack came his sister was prearing supper.
7. I have done my homework. How i can go for a walk.
8. He will look after his brother next week.
9. Pupils didn't visit the boy last week.
10. We don't translate poems at home. 

Какова тема Ревизор??помогите пожолуйста!!