What’s the correct answer for this?

Answer:
54
Step-by-step explanation:
Since diameter AB divides MN into two equal parts hence
MO = NO
NOW,
5x+34 = -2(1-7x)
5x+34 = -2+14x
34+2 = 14x-5x
36 = 9x
Dividing both sides by 9
x = 4
Now,
NO = -2(1-7(4))
NO = -2+56
NO = -2+56
NO = 54