I’ll mark youyou brainlist I’ll mark youyou brainlist

Answer: 30 degrees
Step-by-step explanation:
Since the are supplementary have them equal to 180 (degrees).
(8r + 206) + (7t + 79)= 18
Combine like terms
15r + 295= 180
Subtract 295 from both sides.
15r + 295-295= 180-295
15r = -105
Divide both sides by 15
15r/15= -105/15
r=-7
Solve for the measure of YMB.
Plug in -7 for r.
7(-7) + 79
-49 + 79
30 = YMB