Простое тригонометрическое уравнение, а решить не могу..пипец!  
sin 3х - 
sin х = 0.  

движение тела задано уравнением  х=15+2t+2t^2. определите кинетическуюэнергию телачерез 2с после начала движения. Масса тела 4кг

решите пожалуйста
choose the correct item.
1. ... five teachers at the party.
a) it will be b)there will be
2. what were you ... when I phoned you?
a)discussing  b)been (не понятно что написано)
3. I can help you now. I ...working.
a)cannot b) am not 


correct the mistakes 
1. is it often snow in winter?
2. I don`t know the boy. I never met him.
3.i have been cleaned my room for two hours.
4. she has cooking lunch for an hour.
5. those girls have translated Part Two last Monday.
6. Natasha can`t go. She hadn`t finished her work yet.
7. They discussed everything since two days ago.
8. he is not swiming.he is jumping now.
9.I am thinking that he will be late tomorrow.
10. I have been learning the new words  for ten o`clock.