Résolutions d'équations

Correction exercice 4ème

3 + x = 1 <=> x = 1 - 3 <=> x = - 2

-x - 2 = 2x + 1 <=> - x - 2x = 1 + 2 <=> - 3x = 3 <=> x = - 1

-3x - 2 = 3 + 2x <=> - 3x - 2x = 3 + 2 <=> - 5x = 5 <=> x = - 1

3(x - 4) = 6x + 5 <=> 3x - 12 = 6x + 5 <=> 3x - 6x = 5 + 12 <=> - 3x = 17 <=> x = - 17/3

-(x + 2) = 5x - 1 <=> - x - 2 = 5x - 1 <=> - x - 5x = - 1 + 2 <=> - 6x = 1 <=> x = - 1/6