Trigonometric equation?

ignore whatever is written with pencil. its question 8. If you have time, can you do 8.1 to 8.8 except 8.2 because i have done it.
I know I'm getting too ahead of myself for asking too much to a stranger but i really need to know to do this before exam.

pls ONLY USE COS, SIN and TAN.
Update: these are the answers:
8.1) x=11pi/30 and pi/30
8.3) pi/2 and 3pi/4


i have already got the answers, i need to know how to do it.
2 answers 2