2/(x-1) + 3/(x+1) = 14/(x-3) - 9/(x-2)
[2(x+1) + 3(x-1)]/(x²-1) = [14(x-2) - 9(x-3)]/ [(x-3)(x-2)]
(2x + 2 + 3x - 3)/(x² - 1) = (14x - 28 - 9x + 27)/ (x² - 2x - 3x + 6)
(5x - 1)/(x² - 1) = (5x - 1)/(x² - 5x + 6)
Produit en croix donne:
(5x - 1)(x² - 5x + 6) = (5x - 1)(x² - 1)
On simplifie par 5x - 1
x² - 5x + 6 = x² - 1
x² - 5x + 6 - x² +1 = 0 [et j´avais mis -1, ce qui m´avait donné le x=1 donc impossible :/ ]
x² s´annule (x² - x² = 0)
- 5x + 7 = 0
- 5x = -7
x = -5/-7 = 5/7
