Solve the following math problem step by step. The last line of your response should be of the form Answer: \boxed{$Answer} where $Answer is the answer to the problem.

<image>Find $U B$ if $\triangle R S T \sim \triangle U V W, \overline{T A}$ and $\overline{WB}$ are medians, $T A=8$, $R A=3, W B=3 x-6,$ and $U B=x+2$