Respuesta :

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°

Answer:

B. 120

Step-by-step explanation:

2cos x + 1 = 0

2 cos x = -1

cos x = -1/2

x = cos^1(-1/2)

(cos inverse (-1/2))

x = 120°