You would find the measure of angle U which is 33. Then you would add 8x+12x and get 20x then you would add 33 and 7 and get 40 so you have 20x+40=180 (because all of a triangles measures = 180) then you would minus 40 from both sides you now have 20x=140 then divide by 20 and x=7 then you would go back and do 12(7) . Then your angle = 84