What is the answer to this? (you are also factoring trinomials)

Hello! i hope this
since the cosine is the ratio of the adjacent side to the hypotenuse, you can see that cos 60° = ½. answer. according to the property of cofunctions (topic 3), sin 30° is equal to cos 60°. sin 30° = ½.

Ibelieve it's a. 2.2 - x = -10.85 (plz tell me if it's right : ) )