Bonjour,
a. (2x + 1)(4x – 1) = 0
soit
2x+1 =0
2x= -1
x= -1/2
soit
4x-1 = 0
4x=1
x= 1/4
b. (2x - 9)(-x - 2) = 0
soit
2x-9 = 0
2x= 9
x= 9/2 = 4,5
soit
-x-2 = 0
-2 = x
x= -2
c. (3x - 5)(8 - 2x) = 0
soit
3x-5 = 0
3x = 5
x= 5/3
soit
8-2x = 0
8 =2x
x= 8/2 = 4
d. (10 - 4x) × 7 = 0
10 -4x =0
10 = 4x
x= 10/4 = 5/2