Bonsoir
a. (3х + 1)(х - 5) = 0
3x + 1 = 0 ou x - 5 = 0
3x = - 1 x = 5
x = - 1/3
B.(3x + 7)(4x - 5) = 0
3x + 7 = 0 ou 4x - 5 = 0
3x = - 7 4x = 5
x = - 7/3 x = 5/4
C. 5(9x - 3)( -5x -13 ) = 0
9x - 3 = 0 ou - 5x - 13 = 0
9x = 3 - 5x = 13
x = 3/9 x = - 13/5
x = 1/3