Question 29908
As the problem does not contain any brackets it could be taken as follows:
x-1/3-4 = 3x-8/12 ----(*)
x-[(1/3)+4] = 3x-(8/12)
x-(7/3)=3x-(2/3)
Multiplying by 3
3x-7 =9x-2
3x-9x = 7-2
-6x=5
x =-5/6
Verification: LHS = RHS = (-19/6)
Note:The problem is not clear because the right brackets are not included!
I have tried the problem with two different inclusions of brackets. And if your actual problem is entirely different from these two versions please check and post the correct problem (I mean the problem with the brackets in place!)

[(x-1)/3]-4 = (3x-8)/12 ----(1)
Multiplying by 12 through out
4(x-1)-4X12 = (3x-8)
4x-4-48 = 3x-8
4x-52 = 3x-8
4x-3x= 52-8
x = 44
Verification: x=44 in (1)
LHS = (43/3) - 4 = (43-12)/3 = 31/3
RHS = (3X44-8)/12 = 124/12 =31/3 =RHS

Note: if the problem is
(x-1)/(3-4) = (3x-8)/12  ----(2)
(x-1)/(-1) =(3x-8)/12
Multiplying by (-12)
12(x-1) =-(3x-8)
12x-12 = -3x+8
12x+3x = 8+12
 15x = 20
 x =20/15 = 4X5/3X5 = 4/3
Answer: x= 4/3
Verification: Putting x= 4/3 in (2)
LHS = (4/3-1)/(-1) = (-1/3)
RHs = (3X4/3 -8)/12 = (4-8)/12 = -4/12 = -1/3 = LHS