bonjour je n'y arrive pas du tout . 2(3x+5)=8-x (5x+7)(12-3x)=0

2(3x+5) = 8-x
6x+10 = 8-x
7x = -2
x = -2/7
-------------------
(5x+7)(12-3x) = 0
x = -7/5 ou x = 4

2(3x+5) = 8-x
=> 6x + 10 = 8 -x
=> 6x + x = 8 -10 
=> 7x = -2
=> x = -2/7

(5x+7)(12-3x)=0
=> 5x+7 = 0 ou 12-3x = 0 
=> 5x = -7 ou 12 = 3x
=> x -7/5 ou x=12/3 = 4