Réponse:
a) (4x +5)(x -3) = 0
4x +5 = 0
4x = -5
4x/4 = -5/4
x = -5/4
x -3 = 0
x = 3
L'équation a deux solutions : -5/4 ou 3.
b) x(9x -2) = 0
x = 0
9x -2 = 0
9x = 2
9x/9 = 2/9
x = 2/9
L'équation a deux solutions : 0 ou 2/9 .
c) x² +10x +25 = 0
x² + 2×x×5 +5² = 0
(x +5)² = 0
x +5 = 0
x = -5
d) 36x² -1 = 0
36x² = 1
36x²/36 = 1/36
x² = 1/36
√x² = ±√1/36
x = ±1/6
x = 1/6 ou
x = -1/6
L'équation a deux solutions : 1/6 ou -1/6 .
