The user miscalculated. It should have been (544-243)/486=3x, 301/486=3x, x=301/1458.
The question is ambiguous anyway, because the first fraction could be (272/3)×81=7344 or 272/(3×81)=272/243. If PEMDAS was applied, it would make the first meaning the correct interpretation, not the second, because divide and multiply have the same priority (272 divided by 3 then multiplied by 81).
Parentheses should be used to make the meaning clear and unambiguous.