Cevap :
x² - 2x + 1 - 1 - 3 = 0
(x² - 2x + 1) - 4 = 0
(x - 1)² - 2² = 0
(x - 1 - 2)(x - 1 + 2) = 0
(x - 3)(x + 1) = 0
x = 3 ve x = -1
Ç = {-1, 3}
x² - 2x + 1 - 1 - 3 = 0
(x² - 2x + 1) - 4 = 0
(x - 1)² - 2² = 0
(x - 1 - 2)(x - 1 + 2) = 0
(x - 3)(x + 1) = 0
x = 3 ve x = -1
Ç = {-1, 3}