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30 tháng 6 2021

18. were enjoying 

19. gave

20. was bleeding

21. went

C. Remind

2 tháng 12 2021

C

NV
14 tháng 9 2021

3.

Từ BBT ta thấy hàm đồng biến trên các khoảng \(\left(-\infty;-1\right)\) và \(\left(1;+\infty\right)\)

B đúng

4.

Từ BBT ta thấy hàm đồng biến trên các khoảng \(\left(-\infty;-1\right)\) và \(\left(0;1\right)\)

A đúng

1.

B sai (thiếu điều kiện \(f'\left(x\right)=0\) tại hữu hạn điểm)

14 tháng 9 2021

thầy ơi còn câu 9 vs câu 2 s thầy

 

27 tháng 8 2021

1. If you are calm, you won't make a wrong decision.
2. These wonderful poems were written by a great poet.
3.Because of rained heavily, Jane didn't go fishing yesterday.
4.Vietnamese people use Khue Van pavilion as a symbol of Hanoi.
5. His idea is not the same as me.
6. Those modern paintings are not as expensive as these Dong Ho paintings.
7. What food do you like?
8.These machines are used by chefs to mix the ingredients.
9. It i've most seen such a boring movie.
10. There are not many eggs in the fridge.
11.They started living there 2 years ago.
12. I have never drunk cocktail before.
13.This exercise is not as difficult as the last one.
14. I find playing computer games boring.
15. The new building has the same height as the old one.
16. She didn't have enough eggs to make an omelette.
17. In spite of promising that wouldn't be late, he didn't arrive until 9 o'clock.
18. I didn't use to listen to Western music some years ago.
19. 
My mum used to be a chef in Cham restaurant, but now she is tired.

 

 

 

 

 

 

5 tháng 1 2022

1)

$a)m_{Cl_2} = 0,3.71 = 21,3(gam)$
$b)V_{Cl_2} = 0,3.22,4 = 6,72(lít)$
Số phân tử $= 0,3.6.10^{23} = 1,8.10^{23}$ phân tử

2)

$a)m_{CO_2} = 0,45.44 = 19,8(gam)$
$b) V_{CO_2} = 0,45.22,4 = 10,08(lít)$
Số phân tử $= 0,45.6.10^{23} = 2,7.10^{23}$ phân tử

15 tháng 9 2021

1 B

2 B

3 A

4 D

5 A

6 C

7 D

8 D

9 A

10 C

11 B

12 C

13 B

14 B

15 B

16 D

17 C

18 A

19 B

20 B

III

1 C

2 A

3 C

4 D

5 D

6 B

7 D

8 B

9 D

10 A

11 B

23 tháng 9 2021

T T F T T F

29: Ta có: \(\dfrac{1}{\sqrt{7}+\sqrt{5}}+\dfrac{2}{1-\sqrt{7}}\)

\(=\dfrac{\sqrt{7}-\sqrt{5}}{2}-\dfrac{2\sqrt{7}-2}{6}\)

\(=\dfrac{3\sqrt{7}-3\sqrt{5}-2\sqrt{7}+2}{6}\)

\(=\dfrac{-3\sqrt{5}-2}{6}\)

30: Ta có: \(\dfrac{4}{1-\sqrt{3}}+\dfrac{\sqrt{3}-1}{\sqrt{3}+1}\)

\(=\dfrac{-4\sqrt{3}-4}{2}+\dfrac{4-2\sqrt{3}}{2}\)

\(=\dfrac{-4\sqrt{3}-4+4-2\sqrt{3}}{2}=-3\sqrt{3}\)

31: Ta có: \(\dfrac{1}{\sqrt{2}-\sqrt{3}}-\dfrac{3}{\sqrt{18}+2\sqrt{3}}\)

\(=-\sqrt{3}-\sqrt{2}-\dfrac{3}{3\sqrt{2}+2\sqrt{3}}\)

\(=-\sqrt{3}-\sqrt{2}-\dfrac{9\sqrt{2}-6\sqrt{3}}{6}\)

\(=\dfrac{-6\sqrt{3}-6\sqrt{2}-9\sqrt{2}+6\sqrt{3}}{6}=\dfrac{-15\sqrt{2}}{6}\)

\(=\dfrac{-5\sqrt{2}}{2}\)

AH
Akai Haruma
Giáo viên
23 tháng 8 2021

29.

\(=\frac{\sqrt{7}-\sqrt{5}}{(\sqrt{7}-\sqrt{5})(\sqrt{7}+\sqrt{5})}+\frac{2(1+\sqrt{7})}{(1-\sqrt{7})(1+\sqrt{7})}\)

\(=\frac{\sqrt{7}-\sqrt{5}}{7-5}+\frac{2(1+\sqrt{7})}{1-7}=\frac{\sqrt{7}-\sqrt{5}}{2}-\frac{1+\sqrt{7}}{3}=\frac{\sqrt{7}-3\sqrt{5}-2}{6}\)