1. C

2. B

3. D

4. A

5. D

6. B

7. B

8. D

9. A

10. C

tick mk nha

1. D

2. B

3. D

4. A

5. B

Ko chắc

6.The window was broken and some pictures were taken away by the boys.

7. A lot of money is spent on advertising everyday.

8.A story is going to be told by teacher.

9.English is spoken in almost every corner of the world.

10. This machine mustn't be used after 5:30 pm.

11. Is a poem going to be written?

12. Are big cakes being made for the party 

13. Are inquires about the thief being made by the police

14. must the test be finished before ten?

15. has your homework been finished?

B

1) CHo tứ giác ABCD; M,N,P,Q lần lượt là trung điểm của AB,BC,CD,DA

CM: \(\overrightarrow{NP}=\overrightarrow{MQ}\)  

       \(\overrightarrow{PQ}=\overrightarrow{NM}\)

a) PƯHH: \(CH_4+2O_2\xrightarrow[]{t^0}CO_2\uparrow+2H_2O\)

b) Theo định luật bảo toàn khối lượng, ta có: 

\(m_{CH_4}+m_{O_2}=m_{CO_2}+m_{H_2O}\)

\(\Rightarrow m_{O_2}=m_{CO_2}+m_{H_2O}-m_{CH_4}=44+36-16=64\) (g)

Ta có: \(7.5^{2n}+12.6^n\)

= \(7.5^{2n}+\left(19-7\right).6^n\)

= \(7.5^{2n}+19.6^n-7.6^n\)

= \(7\left(5^{2n}-6^n\right)+19.6^n\)

= \(7\left(25^n-6^n\right)+19.6^n\)

Có: \(19+6^n⋮19\)

\(7\left(25^n-6^n\right)⋮19\)

Vậy...................(đpcm)