If two angles are supplementary, then they add up to 180.
Angle 1 = twenty less than four times the other angle
Angle 2 = the other angle
Angle 2 = 1x
Angle 1 = 4x - 20
Next, we can add up angles 1 and 2 and set the sum equal to 180.
x + 4x - 20 = 180
5x - 20 = 180
5x = 200
x = 40
Now that we know x, we can find the values of our angles.
Angle 1 = 4(40) - 20 = 160 - 20 = 140 degrees
Angle 2 = 40 degrees
Hope this helps!! :)