Aidez moi pour le 8 stp stp

7x=28
x=7

7 + x = 28
7 -7 + x = 28-7
x = 21

-7x = -28
x = 4

7x = -28
x= -4

7-x = 28
7-7 -x = 28-7
-x = 21
x= -21

x-7 = -28
x-7+7 = 28+7
x = 35

7+x = -28
7-7 +x = -28-7
x= -35

x-7 = 28
x-7+7 = 28+7
x=35

-7x = 28
x = -4

7-x = -28
7-7-x = -28-7
-x = -35
x=35


b) Regroupe-les. Cette question est trop bête à mon avis. 

c)  -x-7 =28
-x-7+7 = 28+7
-x = 35
x=-35

-x-7=-28
-x-7+7= -28+7
-x =-21
x = 21