Question 119342
"two angles are supplementary." 
This means the sum of the two angle = 180 degrees
:
One angle measures 30 less than twice the other.
Let one angle = x
the other angle = (2x-30)
:
 What are the measures of the angles?
 x + (2x-30) = 180
 3x = 180 + 30
 3x = 210
  x = 210/3
  x = 70 degrees
:
The other angle = 2(70) - 30 = 110 degrees
:
70 + 110 = 180 as you would expect