The only way you can answer this is if x meets the chord at right angles or if x bisects the chord at the chord's midpoint. Otherwise the problem is unsolvable. Since neither of the two conditions have been met in the givens of the problem, I would say that you can't do it.
However having expressed that opinion, I think whoever gave you the problem expects you to say that since the two chords are equal and since x looks like it bisects the chord, that x = 16 because congruency can be shown.
Answer 16
but its not the best question I've seen.