Question

a)2 ×+8=0 b)5×-4=6×+8 c) 3a-b-c=0

Answer 1

a) 
2x+8 = 0  
2x = -8
x = -8/2
x = - 4

b) 
5x-4 = 6x + 8
5x - 6x = 8 + 4
-x = 12
x = 12/-1
x = - 12 

c)
3a - b - c = 0 
3a = b + c
a = (b + c)/3                     ok

Answer 2

A)  2x + 8 = 0

2x = -8    ==>  x = -8/2  ==>  x = - 4.

B) 5x - 4 = 6

   5x = 6 - 4
   5x =  2
    x =   2/5.

C)  3a - b - c = 0

     3 ( -4) - 2/5 - c = 0

     -12 - 2/5 -c =0

    (  -60 - 2 )/5  - c = 0

       -62/5 - c = 0
       -62 - 5c =0
       - 5c =  + 62
         5c = - 62

         c = - 62/5