Réponses

2013-08-22T18:18:49+02:00
x² + 5x + 6 = - (x -  \frac{5}{2} )² +  \frac{49}{4}
x² + 5x + 6 = - (x² - 5x + 6,25) + 12,25
x² + 5x + 6 = - x² + 5x - 6,25 + 12,25
x² + 5x + 6 = - x² + 5x + 6
x² + x² + 5x - 5x = 6 - 6
2x² = 0
x = 0.