First one:
Supplementary = 180
Add the angles together to get 180
10x + 36 + 6x = 180
16x = 144, x = 9
Plug 9 into equation of angle RAS
10(9) + 36 = 126
Angle RAS = 126 degrees
Second question:
Exterior angle = sun of two opposite interior angles
54 degrees + 90 degrees = 144
Solution: the exterior angle is 144 degrees