Chọn C và Chọn A

b) Áp dụng hệ thức lượng trong tam giác vuông vào ΔAHB vuông tại H có HM là đường cao ứng với cạnh huyền AB, ta được:

\(AM\cdot AB=AH^2\)(1)

Áp dụng hệ thức lượng trong tam giác vuông vào ΔAHC vuông tại H có HN là đường cao ứng với cạnh huyền AC, ta được:

\(AN\cdot AC=AH^2\)(2)

Từ (1) và (2) suy ra \(AM\cdot AB=AN\cdot AC\)

1, Nam isn't so short as Hưng

2,Lan drives to work

3,How many fans are there in the classroom ?

4,It took 15 minutes 

5,Unless she work hard ,giữ nguyên

1 denied stealing his motorbike 

2 suggested going out for dinner that night

3 advised Gilda to study harder

4 apologized for having made a silly mistake

5 predicted that I would be a talented writer

6 boasted that she had never made any mistake in her life

7 promised not to tell a lie again

8 doubted that it would rain the day after

9 ordered to give Kate a lift

10 apologized for having broken the new flower vase 

1 Katherine  denied stealing his motorbike 

2 Katherine suggested going out for dinner that night

3 Katherine advised Gilda to study harder

4 apologized for having made a silly mistake

5  Katherine 

6 boasted that she had never made any mistake in her life

7 promised not to tell a lie again

8 doubted that it would rain the day after

9 ordered to give Kate a lift

10 apologized for having broken the new flower vase 

^{_{1. denied stealing his motorbike}} 

^{_{2. suggested going out for dinner that night}}

^{_{3. advised Gilda to study harder}}

^{_{4. apologized for having made a silly mistake}}

^{_{5. predicted that I would be a talented writer}}

^{_{6. boasted that she had never made any mistake in her life}}

^{_{7. promised not to tell a lie again}}

^{_{8. doubted that it would rain the day after}}

^{_{9. ordered to give Kate a lift}}

^{_{10. apologized for having broken the new flower vase}}