ce exercice 10 svp pouvez vous m'aide avec mon devoir

bonjour

a)( x - 3) x = 1/4 
x = 4 x - 12
x -  4 x = - 12
- 3 x = -12
x = 4 

b)(2 x )/5 = ( x +2)/3 
    6 x = 5 x + 10
    6 x -5 x = 10
    x = 10 

c) 2/7 = x / x - 5 
 7 x = 2 x - 10
 7 x - 2 x = - 10
5 x = - 10
x = - 2

a/
(x - 3)4 = x   
4x - 12 = x   
4x - x = 12 
3x  = 12
x  = 12/3
x = 4


b/
3(2x) = 5(x + 2)  
6x = 5x + 10
6x - 5x  = 10
x  = 10


c/
2 (x - 5) = 7x
2x - 10 = 7x
2x - 7x = 10
 - 5x = 10
x = -10/5
x = - 2