Question 155261
If A and B are suplementary angles, then:
 A+B = 180 and, from the problem:
 A = 4B-15  Substitute this into the above equation and solve for B.
(4B-15)+B = 180 Simplify.
5B-15 = 180  Add 15 to both sides.
5B = 195  Divide both sides by 5.
B = 39 degrees
A = 180-39 Supplementary angles.
A = 141 degrees.