3*y-(4*(2-y)=3(y-4)

3*y-(4*(2-y)=3(y-4)      expand L and R sides

3y -  8+4y  = 3y-12         subtract 3y from both sides

  - 8 + 4y = -12                  add 8 to both sides

          4y = -4                       divide by 4

             y = -1