The answer is b
2cos x + 1 = 0
2 cos x = -1
cos x = -1/2
x = cos^1(-1/2)
(cos inverse (-1/2))
x = 120°
It will come out to a flat number like 10 20 30 40 ect and the counterfeit will have a 1 at the end such as 11 21 31 41.
Hope i Helped
Answer: 3.125
Step-by-step explanation: