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!
Смотри ........................
1)10,3-2,3=8м
2)х-расстояние между вершинами
х^2=8^2+15^2
x=17м-расстояние между вершинами
X^2-4x+1=0
D=(-4)^2-4*1=12
x1= (4-V12)/2=(4-2V3)/2=2-V3 ( V-знак квадратного корня)
x2=(4+V12)/2=2+V3
<span>(-10)^3+(-10)^2+(-10)^0 = </span>1000+100+1= -899