Réponses

2014-09-17T19:24:13+02:00
 f(x)=(x-2)(2x+3)-(x-2)(x+4) = (x-2)(2x+3 - x - 4) = (x-2)(x - 1) = x² -3x + 2 
(x - a)² = x² - 2ax + a² et 2ax = 3.x => a = 3/2
or (x - 3/2)² = x² - 3x + 9/4 donc x² - 3x = (x-3/2)² - 9/4
x² - 3x +2 = 
(x-3/2)² - 9/4 +2 = (x - 3/2)² - 1/4