– let the supplement be ‘x’

– the angle is 3 times x minus 20

– x plus the other angle is 180

Supplement(x) + Angle(3x – 20) = 180

x + (3x – 20) = 180

4x – 20 = 180

4x = 200

x = 50

Angle = 3x – 20

3(50) – 20 = 150 – 20

ANSWER:

Angle = 130 degrees

(The Supplement = 50 degrees)

*Remember, you are looking for the angle that is 20 less than 3 times the supplementary angle, not the supplementary angle itself.

then x= 3(180-x)-20

(180-x) is the supplement of x

ie x= 540-3x-20

x= 520-3x

4x= 520

x=130

therefore, the angle is 130

3x – 20 = 180 – x

4x = 180 + 20

x = 50

therefore, the angle is 130 degrees