bagaimana cara mengerjakan [3,5x - 1.2] = [8,5x + 6]

|3,5x - 1,2| = |8,5x + 6|
(3,5x - 1,2)² - (8,5x + 6)² = 0
(12x - 4,8)(-5x - 7,2) = 0
x = 4,8/12 atau x = 7,2/-5
x = 2/5 atau x = -36/25

HP = {2/5 , -36/25}