вычислите массу осадка полученного при взаимодействия хлорида кальция массой 22.2 г. с карбонатом натрия

график линейной функции проходит через точку А(5;-1) и через точку В(-10;3).задайте функцию формулой ах+ву=с.

надо решить систему { 5а-в=с

                                         {-10а+3в=с

Сократите пожалуйста текст до пересказа)

How the Book Was Born.

-A book is part thing and part thought.

-When we open the book, we find ourselves in a silent wonderful world -We visit foreign shores, we discover hidden treasure, we travel among stars -Man s thoughts and dreams are stored in books.

-From the first books which were made by hand the book has come a long way.

-At first man learnt to draw pictures, later alphabetic writing appeared.

-For a long time papyrus, sheep and goat skins were used to write on.

-Centuries passed, then the Chinese gave us paper.

-To Rome we owe the format of the book; to Germany, the art of printing.

-Indeed, the book was born thanks to the genius and hard work of many people and nations .

-Long, long ago there were very few books because all books were written by hand with pen and ink.

-Some of the books were very beautiful, pictures were painted on each page.

-It took a very long time to write books, often many years were spent to make one copy of a book.

-This made books very expensive and a man who had 20 books was thought to be very rich.

-At last men learned how to print.

-In the middle of the 15th century a German named Johann Gutenberg cut pieces of wood into the shape of letters.

-These letters were made into words, ink was put on them and then the words were pressed on a sheet of paper.

-In this way words were printed on paper and a book was made The first man to print books in England was named William Caxton.

-He was a merchant; in Germany he saw the new way to make books.

-When he had found out all about it, he returned to London and began to print books himself.

-The new books were cheap, so that many people could buy them

-The man who invented the art of printing in Russia is Ivan Fedorov( it was in the 16th

century).

-Ivan Fedorov had his press in Moscow, but his masters were against printing books and made him stop his work.

-Now that the people in our country are among the greatest readers in the world we remember the name of Ivan Fedorov and the year 1574 when his Azbuka was printed. -Ivan Fedorov’s Azbuka helped the people to learn the alphabet and taught them to read books.

-The year of 1574 is the most important event in the cultural life of Russia of the 16th century.

-Today we find it hard to imagine the bookless world of the past, hard to imagine the long way the book has come.

-Now even boys and girls at school have as many books as rich people used to have in the days before men learned to print.

сектор с центральным углом 300 градусов составляет .....круга.