Supplementary angles add up 180°.
So:
M
(2x-24) + (5x-27) = 180
Solve for x:
2x - 24 + 5x - 27 = 180
Combine like terms:
2x + 5x - 24 -27 = 180
7x -51 = 180
7x = 180 +51
7x = 231
x= 231/7
x= 33
Replace x on m
m< B = 5x-27 = 5 (33) - 27 = 165-27 = 138
m