Предмет: Алгебра, автор: Аноним

Помогите пожалуйста пожалуйста пожалуйста

Приложения:

Ответы

Автор ответа: dengaming200518

Ответ:

а12 = а1 + 11*d

d = a2 - a1 = 7 - 3 = 4

a12 = a1 + 11*d = 3 + 11*4 = 47

s12 = (a1 + a12)*12 / 2 = (3 + 47)*6 = 300

Предыдущий вопрос

Следующий вопрос

Похожие вопросы

Предмет: Английский язык, автор: eleusinova1981

the boring speaker droned on for an hour

1 год назад

Предмет: Английский язык, автор: 19tatyana74

Where is Tony?a)At home,d)At the swimming pool,c)At the shops,d) At the sports ground

1 год назад

Предмет: Українська література, автор: Аноним

коротка характеристика всых образыв з Наталки Полтавки

1 год назад

Предмет: Английский язык, автор: Mashaa869

Choose the correct answer.

1. What’s ______ job? She is a hotel manager.

a) my b) your c) his d) her

2. Anita usually likes coffee, but now she ______ tea.

a) drank b) drink c) is drinking d) drinks

3. Is ______ your pen over there?

a) that b) this c) these d) those

4. There are ______ magazines on the shelf.

a) any b) some c) a d) the

5. No news ______ good news.

a) is b) are c) — d) am

6. The man is old and he can't ______ well.

a) heard b) to hear c) hear d) listen

7. He could open the lock ______.

a) easy b) most easy c) easily d) easiest

8. The information is top secret, so naturally, everybody is interested in ______.

a) them b) her c) their d) it

9. There isn’t ______ water in the bottle.

a) many b) few c) much d) a few

10. Their house is ______ than ours.

a) more smaller b) the smallest c) smallest d) smaller

11. Who ______ after their small kids? — Their grandparents do.

a) do looks b) looks c) do look d) look

12. Just look at ______ in the mirror. You are so dirty.

a) your b) oneself c) yours d) yourself

13. I am very proud of my sister. She ______ the guitar and the piano.

a) cans play b) can plays c) can play d) can to play

14. Do you listen to opera? – No, I ______ listen to opera. I hate it.

a) always b) never c) often d) usually

15.They looked ______ each other in surprise.

a) with b) for c) at d) after

16. We are flying to Sochi on ______.

a) seven July b) the seventh of July c) seventh of July d) the seven of July

17. I can’t play football. I ______ my arm yesterday.

a) breaked b) broked c) broke d) broken
помогите пожалуйста

8 лет назад

Предмет: Математика, автор: Эмма28072006

помогите по математике 10,11,12

8 лет назад