Решить системы: х *у=171,х+у=28 х+у=3, х^2+y^2=65

1)   НАЙДИ значения выражений 3600:b, 3600*b, если b=48; b=24; b=15; b=50; b=5.  расписать      2)    10000-(10+910*85:65)=       12000:(840-280*96:42)=      67068:324=                226720:436=

 Пожалуйста решите задания с 1 по 4.

№ 1  Найдите длину окружности, радиус которой равен: 20 см.

№ 2  Найдите длину  окружности, диаметр которой равен: 180 мм. 

№3   Найдите  радиус окружности, длина  которой равена: 62,8 дм.

№4   Длина веревки, обвитой вокруг бревна, равна: 1,6 м. Какова толщина бревна?

Решите  2(d-5)d-(d+1)^3

Упражнения 1. Раскройте скобки, употребляя гла­голы в Past Simple или Past Continuous.

1.I (to play) computer games yesterday. 2. I (to play) computer games at five o'clock yesterday. 3. He (to play) computer games from two till three yesterday. 4. We (to play) computer games the whole evening yesterday. 5. What Nick (to do) when you came to his place? 6. What you (to do) when I rang you up? 7. I (not to sleep) at nine o'clock yesterday. 8. What he (to do) yesterday? - He (to read) a book. 9. What he (to do) the whole evening yesterday? --He (to read) a book. 10. She (to sleep) when you came home? 11. My brother (not to play) tennis yesterday. He (to play) tennis the day be­fore yesterday. 12. My sister (not to play) the pi­ano at four o'clock yesterday. She (to play) the piano the whole evening. 13. When I came into the kitchen, mother (to cook). 14. She (to cook) the whole day yesterday. 15. We (to wash) the floor in our flat yesterday. 16. We (to wash) the floor in our flat from three till four yesterday. 17. You (to do) your homework yesterday? 18. You (to do) your homework from eight till ten yesterday? 19. Why she (to sleep) at seven o'clock yesterday? 20. He (to sit) at the table the whole evening yesterday.