Choose the right answer
4. There isn't a cloud in the sky,... ?
A ..., is it? В ..., does it? С ..., is there?
5. Sam doesn't work hard,... ?
A ..., is he? В ..., does he? С ..., isn't he?
6. I'd like to have... hamburger for... breakfast.
A the В а
С an D -
7. Can you play... piano?
A the В а
С an D -
8. My favourite subject at school is... History.
A the В а
С an D -
9 Queen Elizabeth II won't speak on TV tomorrow.
A the В -
10 Houses of Parliament has over 1,000 rooms, and 2 miles of corridors.
A the В -
11. My mother... a bad headache.
A have got
В am
С has got
12 you (like) swimming?
A Do you like
В Does you like
С Are you like
13 Jane Smith (speak) English?
A Is ... speak В Does ... speak С Do ... speaks
14. Can you help me? I (not / know) the way to the market.
A am not know В not know С don't know
15. We ... a car, but we are going to buy it.
A don't have В aren't have С hasn't
35,8 - х = 1,3 * 2,1 283 - х = 17,01 : 0,9
35,8 - х = 2,73 283 - х = 18,9
х = 35,8 - 2,73 х = 283 - 18,9
х = 33,07 х = 264,1
Проверка: (35,8 - 33,07) : 2,1 = 1,3 Проверка: 0,9(283 - 264,1) = 17,01
2,73 : 2,1 = 1,3 0,9 * 18,9 = 17,01
1,3 = 1,3 17,01 = 17,01
6sinxcosx=5*(cos^2x - sin^2x)
6sinxcosx=5cos^2x - 5sin^2x
5sin^2x + 6cosxsinx - 5cos^2x = 0 /:cos^2x ≠ 0
однородное уравнение второй степени
5tg^2x + 6tgx - 5 = 0
Пусть tgx = t, причём t ∈ (- беск; + беск )
Тогда решим кв. уравнение:
5t^2 + 6t - 5 = 0
D = 36 + 4*5*5 = 36 + 100 = 136
√D = √136 = 2√34
t1 = ( - 6 + 2√34)/ 10 = ( - 3 + √34)/ 5
t2 = ( - 6 - 2√34)/ 10 = ( - 3 - √34)/ 5
tgx = ( - 3 + √34)/ 5
x = arctg ( - 3 + √34)/ 5 + pik, k ∈Z
tgx = ( - 3 - √34)/ 5
x = arctg ( - 3 - √34)/ 5 + pik, k ∈Z