Which of the following statements correctly illustrate the addition property of equality?
1) If a = b, then a + c = b + c.
2) If x = y, then x + 2 = y - 2.
3) If w + 2 = 7, then w + 2 - 2 = 7 - 2.
4) If z - 2/5 = 9, then z - 2/5 + 2/5 = 9 - 2/5.