Réponses

2014-02-23T21:16:05+01:00
Bonsoir 
-0.2x² + 1.1x +0.9 = 0 
on calcule le delta ou discriminant 
delta ( ou discriminant) = b²-4ac = 1.1² - 4( -0.2)(0.9) = 1.21 + 0.72 = 1.93 
Vdelta = 1.389       ( V  veut dire racine)
deux solutions  
x = (-b-Vdelta)/2a = (-1.1 - 1.389)/-0.4 = 6.2225
x" = (-b +Vdelta)/2a = (-1.1 + 1.389)/-0.4 = - 0.7225