a: \(\widehat{xOm};\widehat{nOm}\)

\(\widehat{nOm};\widehat{yOn}\)

\(\widehat{yOn};\widehat{xOn}\)

\(\widehat{xOm};\widehat{yOm}\)

b: \(\widehat{yOn};\widehat{xOn}\)

\(\widehat{xOm};\widehat{yOm}\)

c: \(\widehat{mOy}=180^0-30^0=150^0\)

\(\widehat{nOx}=180^0-50^0=130^0\)

\(\widehat{mOn}=180^0-80^0=100^0\)

Bài 129:

d: \(\Leftrightarrow x+1=3\)

hay x=2

`@` `\text {Ans}`

`\downarrow`

\(-7\in\text{N}\)

\(-7\in\text{Z}\)

\(-7\in\text{Q}\)

\(-\dfrac{5}{7}\notin\text{Z}\)

\(-\dfrac{5}{7}\in\text{Q}\)

Câu 1: C

CB=8-4=4(cm)

--> C là trung điểm AB

BC là :AB-AC=8-4=4 (cm) 

=> C là trung điểm AB

1. Products

2. disappointingly

3. consuming

4. polluting

5. respiratory

6. seriously

7. harmful

8. Conservationists

9. deforestation

10. necessary

11. celebrations

12. ineffectively

13. innovations

14. respiratory

15. respiratory