\(\dfrac{a}{2}=\dfrac{b}{3}=\dfrac{c}{6}=\dfrac{a+b-c}{2+3-6}=\dfrac{7}{-1}=-7\) 

\(\dfrac{a}{2}=-7\Rightarrow a=-14\)

\(\dfrac{b}{3}=-7\Rightarrow b=-21\)

 \(\dfrac{c}{6}=-7\Rightarrow c=-42\)

Vậy a=-14, b=-21, c=-42

It is important that you do your homework before you go to class.

1. a few 

2. a little

3. a few 

4. a few

5. a little 

6. a few 

7. a little

8. a little 

9. a few 

10. a little 

11. little

12. little 

13. a few 

14. a few

15. a few 

a)\(\dfrac{2\times6^9-2^5\times18^4}{2^2\times6^8}\)   

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