Multiple choice general knowledge math & puzzles If 2x-y=4 then 6x-3y=? 15 10 12 18 Reveal answer Fill a bubble to check yourself C Correct answer Explanation Given 2x - y = 4. To find 6x - 3y, notice that 6x - 3y = 3(2x - y). Substituting the given value: 3(4) = 12. This is a direct application of multiplying both sides of an equation by a constant.