il faut passer les x ou t ou a ou y d'un coté et les nombres de l'autre
a = 7x - 6 = 4 - 3x
a = -7x + 3x = 4 + 6
a = -4x = 10
a = x = -4/10 = -2 /5
b = 12 - a = 18 - 3a
b = 12-18 = a - 3a
b = -6 = -2a
b = -2a/-6 = a = 1/3
13x + 11 = 8 x + 28
13 x - 8 x = 28 - 11
21 x = 17
x = 17/21
- t - 4 = 8 + 7 t
-t -7t =8 + 4
-8 t = 12
t = - 12/8 = -3/2
5x = 0 x = 0
7y + 22 = 14 - 4 y
7 y +4 y = 14 - 22
11 y = - 8
y = -8/11
