Find four solutions for the following equation: x + y = 0

x + y = 0
Take x =1, 1+y = 0
              ∴ y = -1
Take x = 2, 2+y = 0
              ∴y = -2
Take x = 3, 3+y = 0
              ∴ y = -3
Take x = 4, 4+y = 0
              ∴ y = -4
∴The four solutions of the given equation are x = 1, y = -1; x = 2, y = -2; x = 3, y = -3 and x = 4, y = -4.