Factorisation of x² - 4xy + 4y² is

1. (x + 2y)(x - 2y)

2. (x + 2y)(x + 2y)

3. (x - 2y)(x - 2y)

4. (2x - y)(2x + y)

Which of the following is a factor of (x + y)³ - (x³ + y³)?

1. x² + xy + 2xy

2. x² + y² - xy

3. xy²

4. 3xy

If a + b + c = 0, then the value of a³ + b³ + c³ is

1. 0

2. abc

3. 2abc

4. 3abc