Identify the mathematical expression and its components.

The image displays a mathematical expression:

• The expression starts with the letter 'a)' indicating it is part of a list or problem set.
• The mathematical expression is 2xy - 6y².
• Following the expression, there is a semicolon ';'.
• After the semicolon, the number 6 is present.

Therefore, the components are: 'a)', the expression '2xy - 6y²', a semicolon ';', and the number '6'.