1/12 (48+24b) = 2(17-4b)
to make both sides simple, multiply both of the numbers inside of (the round bracket),
(48/12 + 24b/12) = (2x17 - 2x4b)
4 +2b = 34 - 8b
subtract 4 on both sides,
4 + 2b - 4 = 34 - 8b - 4
2b = 30 - 8b
add 8b on both sides,
2b + 8b = 30 - 8b + 8b
10b = 30
divide with 10, on both sides,
10b/10 = 30/10
b = 3
The answer is,
b = 3