The answer is 133°
Supplementary means that the two angles add up to 180°. The word problem defines the following equation:
x + (3x - 8) = 180, where
x is the smaller angle, and
(3x - 8) is the larger angle (they add up to 180)
when we solve for x we get that x = 47
we plug that into the equation for the larger angle like so:
(3x - 8) = (3*47 - 8) = (141 - 8) = 133°
Hope this helped!