Angles S, T and SUT must add to 180 degrees because they're the interior angles of a triangle. The angles at point U (SUT and FUT) are supplementary, so they also add to 180 degrees. This means \(SUT=180-(18x+2)=178-18x\).
So,
\((2x+3)+95+(178-18x)=180\)
\(-16x+276=180\)
\(96=16x\)
\(x=6\)