Réponses

2014-01-22T20:07:42+01:00
Meilleure réponse !
2014-01-22T20:10:08+01:00
25x² = 20x-4
25x² - 20x + 4 = 0
25x² - 10x - 10x + 4 = 0
5x(5x-2) 2(-5x+2) = 0
(5x-2)(5x+2) = 0
(5x)²-2² = 0
25x² - 4 = 0
25x² = 4
x² = 4/25
x = racine de 4/25
x = 2/5