Прочитайте текст и определите какой из заголовков соответствует тексту In algebra letters are used t...: ответ на тест 800509 - Английский язык

Прочитайте текст и определите, какой из заголовков соответствует тексту
In algebra, letters are used to express the general properties of numbers. Representing one number by the letter a and another by the letter b, we can write the equality.
                                   a x b=b x a
or, more shortly, ab=ba.
If no other sign is indicated, the multiplication sign is understood between any two letters written side by side.
To represent numbers letters of the Latin alphabet are generally used.