1) My parnts know so much because they have already travelled a lot.
2) We haven't seen George since last year.
3) I haven't seen this film yet.
4)Alice has just met her friend.
6) The kids have just played in the yard
5) I have never spoken to our teacher.
7) We haven't decided to help him yet.
8) I haven't seen my family for a long time.
9) Have you ever ridden the scooter.
10) Sara has never been snorkelling. She is so inactive!
Решение смотри на фотографии
Добрый день! Решение см. фото.
Sin60° - tg210° = 1/2 - tg(180° + 30°) = 0,5 - tg30° = 0,5 - √3/3
Формула приведения для тангенса:
tg(A + 180°) = tg180°
<span>−3x−(4x−(5x−1))=-3x-(4x-5x+1)=-3x-(1-x)=-3x-1+x=-2x-1</span>