рассчитайте массу водорода, образованного при взаимодействии 48 г. магния с соляной кислотой

РЕШИТЬ УРАВНЕНИЕ (21x+23)/10=27,ПОМОГИТЕ ПОЖАЛУЙСТА

окружность определения,взаимное расположение прямой и окружности

1.On the 12 June the Russian people celebrate 
а) Easter b) Russia Day c) Constitution Day
2.The official name of our homeland is
а) Russia b) the Russian Federation c) the Republic

of the Russian

Federation
3.“Break a leg” means
а) Thank you b) Excuse me c) Good luck

4.In autumn the British have the following traditions and festivals:
а) – the State Opening b) – The trooping of the c) – St David’s

of Parliament Colours Day
5.Guy Fawkes Day - Swan Upping - May Day

During the State Opening of Parliament the Queen sits on the throne in
а) the House of Commons b) the House of Lords c) Buckingham Palace

6.A.A.Milne wa a British writer. He wrote 
а) Harry Potter b) Robinson Crusoe c) Winnis-the-Pooh

7.The earliest books were written on
а) tablets of wood or b) on pieces of cloth c) on pieces of paper

pieces of bark

8.Theatre was born in
а) China b) Britain c) Greece

9.What is Leonardo da Vinci best known for?
а) sculpture b) painting c) designing

10.Who wrote the line “Happy families are all alike, every unhappy family is unhappy in its own way”?
а) Tolstoy b) Dickens c) Shakespeare