Bonsoir,
a)
x( x-9)
soit
x= 0
x-9 = 0
x= 9
b)
(4x+1) ( 7 -6x) =0
4x+1= 0
4x=-1
x = -1/4
7-6x= 0
7 = 6x
x = 7/6
c)
(3x+7)² -25 = 0
identité remarquable
(3x+7 -5) ( 3x+7+5) =0
(3x +2) ( 3x +12) = 0
3x+2 =0
3x= -2
x = -2/3
3x+12 = 0
3x=-12
x= -12/3
x= -4
d)
3x-5+4x -11 = 0
7x -16 = 0
7x =16
x= 16/7
