Let x = the angle
The complement of the angle = 90° - x
The supplement of the angle = 180° - x
So, 90 - x = (1/4)(180 - x) - 6
Multiply the equation by 4 to get 360 - 4x = 180 - x - 24
360 - 4x = 156 - x
204 = 3x
x = 68°