Réponses

2014-05-25T11:48:22+02:00
(2x²-8)(40-2x)=0 => 2x² - 8 = 0 => 2(x² - 4) = 0 => 2(x-2)(x+2) = 0 => x = 2 ou x = -2
                        => 40 - 2x = 0 => 2x = 40 => x = 20
(x-5)²+4x=(x-7)² => x² - 10x + 25 + 4x = x² - 14x + 49 => 8x = 24 => x = 3 
7x+3<6x+2 => x < -1 
-2-(x-2)>8-5x => -2 -x + 2 > 8 - 5x => 4x > 8 => x > 2
10(3x+2)>10(x+5) => 30x + 20 > 10x + 50 => 20x > 30 => x > 3/2