Bonjour,
A) (3x +1)(x - 9)= 0
a = 3x + 1 = 0 b = x - 9 = 0
a = 3x = -1 b = x = 9
a = x = -1 / 3
S = (-1/3 ; 9)
B) (6x + 7)(4x - 11) = 0
a = 6x + 7 = 0 b = 4x - 11 = 0
a = 6x = -7 b = 4x = 11
a = x = -7/6 b = x = 11 / 4
S = (-7/6 ; 11/4)
C) (9x - 3)(- 5x - 13) = 0
a = 9x -3 = 0 b = -5x - 13 = 0
a = 9x = 3 b = -5x = 13
a = x = 3/9 b = x = 13/-5 = [tex]-\frac{13}{5}[/tex]
a = x = 1/3
S = (1/3 ; [tex]-\frac{13}{5}[/tex])
