А12= а9 + 3d а12= 11 + 3 * 2 = 11 + 6 =17 a1 = a9 - 8d = 11 - 8 * 2 = 11- 16 = -7 S12 = (a1+ a12) : 2 * 12 =( -7 + 17)^2 *12= 10^2 *12 = 5*12 = 60
F(17)=-5/17=-0, 294.....=-0,3
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!
Ответ: медиана равна 144. Среднее прифметическое равно 0,2*(136+138+144+152+160)=146. Среднее арияметическое больше медианы на 146-144=2.
Объяснение: