To solve for Vo, one would need to x(t) and t, then it would be just a matter of rearranging the terms, or one writes
(x(t) - xo - 1/2 at2)/t = Vo, or
(x(t) - xo)/t - 1/2 at = Vo
So I'm puzzled about the question.
Finding Vo depends on what other variables are known, and applying the appropriate equation of motion. Does one assume that acceleration is constant?