c=2
28-(3c+4)=2(c+6)+c
1. get #'s out of parentheses
28-3c-4=2c+12+c
2. combine like terms
24-3c=3c+12
3. put the C's on one side and #'s on the other
subtract -12 from 24 and at +3c to the 3c
12=6c
4. then divide the 6 off to leave C all by itself
12/6=c
5. that gives you your answer
2=c