Réponses

2014-09-14T11:21:04+02:00
(x+2)² - (x+1)² = 1

x² + 4x + 4 - (x² + 2x + 1) = 1

x² + 4x + 4 - x² - 2x - 1 = 1

2x + 3 = 1

2x = -2

x = -1