(x - 1)(x + 1), ||x| - 1| = x + 1, | x + 1 | = x + 1, (x+1)(x-1), √x - 1/√x + 1, (√x + 1) . (√x + 1), √x - 1/√x = 1, (x-1).(x+1), (x + 1)³ + (x - 1)³, |x+1|+|x-1|, (x+1):(x-1), (x-1)³+(x-1)², (x + 1) : (x - 1)