I am pretty sure that the answer is the first one but I’m not 100%
Cos 210° = cos ( 180° + 30° ) - cos 30° = - √3/2
Answer: y = -1/2
Step-by-step explanation:
Subtract both sides by 7/8
y = 3/8 - 7/8
Then combine like terms
y = -4/8
Then simplify
y = -1/2
