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Grammar test. Choose the correct answer. 1. Helen ….. to Paris at 5:00 tomorrow morning.
a) flies b) was flying c) is flying

2. They ….. in that house for six years.
a) have lived b) are living c) live

3. It is hard to concentrate ….. your work when there is a lot of noise.
a) in b) on c) to

4. They often ….. on holiday abroad when they were young.
a) went b) go c) have gone

5. Mary ….. every day for the last two months.
a) exercises b) is exercising c) has been exercising

6. My sister works …… an insurance company.
a) to b) on c) for

7. My brother ….. to work by the time I woke up.
a) is going b) has already gone c) had already gone

8. The river Amazon ….. into the Atlantic ocean.
a) is flowing b) flows c) flowed

9. They ….. for four hours when they stopped for a rest.
a) have been driving b) had been driving c) were driving

10. Sam ….. Sue since he was five years old.
a) has known b) knows c) have known

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Ответ:

получается делаем так:

сначала решаем уравнение как и обычно т.е. теоремой виетта или дискриминантом

х^2-4х+3=0

я решу теоремой виетта:

сумма корней равна 4

произведение 3

значит корни 1 и 3

далее:

есть такая формула разложение на множетели квадратного уравнения выглядит так:                 a(x-x1)(x-x2), где а-множетель перед квадратом в нашем случае это 1, х1 и х2 - корни. 

подставим в неё наши корни, получим  (x-1)(x-3)=0

так а теперь решим это неравенство  (x-1)(x-3)> 0

методом интегралов ( тут 3 промежутка от минус бесконечности до 1 от 1 до 3 и от 3 до плюс бесконечности):

допустим х =0, подставим (0-1)(0-3)=3 знак + значит в промежутке от минус бесконечности до 1 знак + 

от 1 до 3 знак -

от 3 до плюс бесконечности +

ответ: х принадлежит промежутку  от минус бесконечности до 1 и  от 3 до плюс бесконечности

4,5(100 оценок)
Ответ:
otvet12313434
otvet12313434
02.11.2021

1 he taught history at school

he didn't teach history at school

did he teach history at school?

2 they left home at 8 o'clock

they did not leave home at 8 o'clock

did they leave home at 8 o'clock?

3 he stood in very good hotels

he didn't stay in very good hotels

did he stay in very good hotels?

4 you drank a lot of tea

you didn't drink a lot of tea

did you drink a lot  of tea?

5 l looked tired

l didn't look tired

did l look tired?

6 we stopped in LONDON

WE DIDN'T STOP IN LONDON

DID WE STOP IN Londn?

7 pam BOUGHT A LOT OF CLOTHES

PAM DIDN'T BUY A LOT OF CLOTHES

DID PAM BYU A LOT OF CLOTHES?

8 birds flEW AWAY TO THEIR COUNTRIES

BIRDS DIDN'T FLY  AWAY TO THEIR COUNTRIES

DID BIRDS FLY TO THEIR COUNTRIES?

4,5(28 оценок)
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