6c-8-2c= -16 works this out and solve, !

6c-8-2c= -16

1st) reduce 6c - 2c = 4c, now te equation becomes:
4c - 8 = -16

2nd) add +8 to the left and right sides

4c - 8 + 8 = - 16 + 8

3rd) reduce the left and right sides:

4c + 0 = -8 → 4c = -8

4t) divide both sides by 4:
4c/4 = -8/4
and c = -2

Google it that might work