First, m<UTS=m<UTV+m<VTS by Angle Addition Postulate. Then, you substitute all the values that you provided for the angles. 15x+15=x+15+140. You then solve for x.
15x+15=x+155
14x=140
x=10
You then plug back in 10 for X in the value of m<UTS. 15(10)+15=165
