|x-1|=|2x+3|
⇔(x +1)² = (2x + 3)²
⇔x² + 2x + 1 = 4x² + 12x + 9
⇔x² + 2x + 1 - 4x² - 12x - 9 = 0
⇔-3x² - 10x - 8 = 0
⇔-3x² - 6x - 4x - 8 = 0
⇔-3x(x + 2) - 4(x + 2) = 0
⇔-(x + 2)(3x + 4) = 0
TH1: x + 2 = 0
x = -2
TH2: 3x + 4 = 0
3x = -4
x = -4/3
S = {-2;-4/3}