pourier vous m'aider svp

Bonjour : 

- t - 4 = 8 + 7t 
- t - 7t - 4 = 8 
- t - 7t = 4 + 8 
-8t= 12
t= -8/12 

13x + 11 = 8x + 28 
13x - 8x + 11 = 28 
13x - 8x = -11 + 28
5x = 17 
x= 5/17 

 -t - 4 = 8 + 7t
 -8t = 8 + 4
  t = -12/8
    = - 3/2


13x + 11 = 8x + 28
13x - 8x = 28 - 11
5x = 17
x = 17/5