Мастер делает 20 деталей в час, а ученик только 12. Работая одновременно, мастер и ученик выполнили заказ по изготовлению деталей за 3/4 часа. Сколько деталей изготовил мастер с учеником ?( с пояснением пожалуйста)

Разложите на множетели многочлен x+y-x^3-y^3

Употребить глаголы в нужной форме в Present Perfect, Past Simple, Past continuos, Past Perfect

1. Theu are happy because their child (to enter) the university. 

2. It ( to be) great to see her last week 

3/ Sorry I (not to phone) you earlier. 

4/ He was very soory to hear that you (not to come) in time. 

5. Whenever I (to drive) past that restaurant, there always (to be) a lot of people. 

6. You ever (to be) to an open-air concert ? 

7. My parents were angry because I (not pass) my exam. 

8. His brother told him that he (to eat) all the fruit which he (to buy) 

9. At this time two  weeks ago we (to lie) on the beach.

10. Beth (to becime) pale when she heard the news

11. I (not to be) impressed with his new car when I (to see) it yesterday.

12. The Aztecs (to be) an American Indian tribe who (to live) in Mexico.

13. Yesterday when I (to look) out of my window, I (to see) that my children (to run) in the garden.

14. I ws sure he always (to be) your best friend

15. Janet never (to take) part in the concerts

16. When she (to come) home, her son (to have) supper.

17. I (to read) all the articles before mother (to come) 

Помогите плиззз(( надо выборочно написать сочинение на темы: СЛОВО – ИСТОЧНИК СЧАСТЬЯ

Почему жизнь сравнивают с путешествием)))

спасибо))