Question 206787
Let's call the missing angle A.
Then its supplement is 180-A, so...
180-A = 3A+20 "...the supplement...is 20 degrees more than 3 times the...angle"
Simplify and solve for A. Subtract 20 from both sides.
160-A = 3A Add A to both sides.
160 = 4A Divide both sides by 4.
40 = A and 180-A = 140
The two angles are:
40 degrees and 140 degrees.