|X-1|²-|X-1|-6=0 help me

|x-1| = {x-1 untuk x >= 1, -x+1 untuk x < 1
(x-1)^2 - (x-1) = 6
x^2 - 2x + 1 - x + 1 - 6 = 0
x^2 - 3x - 4 = 0
(x-4)(x+1) = 0
x-4 = 0
x = 4 (M)
x+1 = 0
x = -1 (TM)

(-x+1)^2 - (-x+1) = 6
x^2 - 2x + 1 + x - 1 - 6 = 0
x^2 - x - 6 = 0
(x-3)(x+2) = 0
x-3 = 0
x = 3 (TM)
x+2 = 0
x = -2 (M)

HP = {-2, 4}