To find the possible values of x, first we mus simplify the inequality -18 + 6x ≥ 4x + 12 6x - 4x ≥ 12 + 18 2x ≥ 30 x ≥ 15 From this, it can be seen that as long as x is equal or more than 15, then it will satify the equation. In mathematicl expression, that means [15, ∞). Thus, the answer is D: [15, ∞).