3(x - 4) = 3x - 12 (expand the brackets)
3x - 12 = 2x + 6
3x = 2x + 6 + 12 (put all of the integers on one side)
3x = 2x + 18 (simplify - collect like terms)
3x - 2x = 18 (put all of the unknowns on one side)
x = 18 (simplify - collect like terms)
Therefore, we know that x is equal to 18, and so the answer is E.
