the 25th letter of the English alphabet
Ví dụ:
- ‘Year’ begins with (a) Y/‘Y’.
used to represent a number whose value is not mentioned
Ví dụ:
- Can the value of y be predicted from the value of x?
a person, a number, an influence, etc. that is not known or not named
Ví dụ:
- Let's suppose X knows what Y is doing.