Résoudre l'équation : x / x+1 = 2x+1 / 2x-1
x(2x-1) = (2x+1)(x+1)
2x²-x= 2x² + 2x +x +1
2x² - x = 2x² +3x +1
4x +1 = 0
x = 1/4
