Answer:
180 - 117 = 63
so...
(3x -3 ) +(x) + 63 = 180
4x +60 = 180
4x = 180 - 60
4x = 120
x =30
x=30, 3x-30=60
sum of angles on a straight line =180
therefore, 180-117=63
then, sum of angles in a triangle=180
3x-3+x+63=180
4x+60=180
4x=180-60
4x=120
x=30
3x-30=3(30)-30=60
