Two angles are supplementary if their sum is 180. the larger angle measures thirty degrees more than twice the measure of a smaller angle

(I'm assuming we're finding the measurement of the smaller angle)

Let's say the smaller angle is x.
That means that the larger angle is 30 + 2x.
If we add the smaller and larger angle together, we get 180.

x + 30 + 2x = 180

Combine like terms
3x + 30 = 180

Subtract 30 on both sides
3x = 150

Divide 3 on both sides,
x = 50

So the smaller angle is 50 degrees :)