1. interested

2. sunny

3. distance

4. warmly

5. performance

6. appearance

7. unhappily 

8. interesting

9. pollution

10. preparation

11. healthy

12. informative

13. enjoyable

14. carelessness

15. developments

16. safely

17. Polluted

18. impression

19. amazingly

1. development

2. religion

3. useful

4. well

5. arrival

6. designers

7. homeless

8. unhappy

9. modernized

10. interesting

11. disastrous

12. Traditionally

13. editor

14. available

15. enjoyable

16. exactly

17. pride

18. differences

19. correspondence

1. development

2. religion

3. useful

4. well

5. arrival

6. designers

7. homeless

8. unhappy

9. modernized

10. interesting

11. disastrous

12. Traditionally

13. editor

14. available

15. enjoyable

16. exactly

17. pride

18. differences

19. correspondence

#Cái này là bài đúng nheaa

1. choice

2. inventions

3. musicians

4. useful

5. necessaries

6. solution

7. destruction

8. healthy

9. majority

10. development

1. development

2. religious

3. useful

4. well

5. arrival

6. designers

7. homeless

8. unhappy

9. modernized

10. interesting

11. disastrous

12. Traditionally

13. editor

14. available

15. enjoyable

16. exactly

17. pride

18. differences

19. correspondence 

20. flights

21. information

22. increasingly

23. invention

24. unnecessary

25. musicians

26. convenience

27. difficulties

28. produce

29. beauty

30. preparation

31. reasoned

32. celebration

33. happiness

20. flights

21. information

22. increasingly

23. invention

24. unnecessary

25. musicians

26. convenience

27. difficulties

28. produce

29. beauty

30. preparation

31. reasoned

32. celebration

33. happiness

a) \(\left\{{}\begin{matrix}2x+y=1\\3x+4y=-1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}y=1-2x\\3x+4\left(1-2x\right)=-1\end{matrix}\right.\Leftrightarrow}\left\{{}\begin{matrix}y=1-2x\\-5x=-5\end{matrix}\right.\Leftrightarrow}\left\{{}\begin{matrix}y=-1\\x=1\end{matrix}\right.\)

Vậy \(\left(x;y\right)=\left(1;-1\right)\)

 1. If people don't enough exercise, there will be lots of heart diseases.

2.If you don't eat healthily, you will get obesity.

3. If these children don't eat too many sweets, they will have bad teeth.

4. If the air is fresh, old people will healthy.

5. If he is tall enough, he will play the game of volleyball.

6. If his mom is here now, she can help him.

7. Unless they invited her to the party, she won't accept their invitation.

8. If you can speak English well, they can offer you a well-paid job.