A polynomial in x is x³ + 5x² - kx - 24. Which of the following is a factor of the given polynomial so that the value of k is 2?

1. (x + 2)

2. (x - 3)

3. (x + 4)

4. (x - 4)

If the sum of n terms of an arithmetic progression S_n = n² - n, then the third term of the series is :

1. 2

2. 4

3. 6

4. 9