Answer:
x = {120°, 240°}
Step-by-step explanation:
cos x = -1/2 for 0 ≤ x ≤ 360°
That cosine of x = -1/2 tells us two things immediately: 1) the hypotenuse has length 2 and the side adjacent to the angle x is -1. To have a negative adjacent side, angle x must be in either Quadrant II or Quadrant III.
If in Quadrant II, the terminal side of angle x is 30° past 90°, which means that x = 120°. If in Quadrant III, the terminal side of x is 30° short of 270°, which means that x = 240°
Then x = {120°, 240°}
