1. My friend asked if I like dancing.

2. Hoa asked me what I was doing.

3. The teacher asked Quang where his father worked.

4. Ha asked Nam if there were any interesting programs on TV that day.

5. Lan asked David how often he visited his home village.

6. Nga asked Tom if he wanted to live on another planet.

7. The boy asked me if that was my new classmate.

8. My friend asked what time I was going to leave the next day.

9. The teacher asked his student if he knew how to reduce garbage in public.

10. Tim asked Nancy if she was doing her math homework then.

11. The old woman asked me when the train S9 to HCM city left.

12. Huong asked Nam if his house was near Ben Thuy Bridge.

13. I asked her when she would have a plumber repair her pipes.

14. He asked her if her students could communicate with foreigners.

15. Hoa asked Nam how many languages his teacher could speak.

16. The guide asked us if we wanted to visit other interesting places in that town.

17. My younger brother asked me what the next stage in the development of TV was.

18. Mr Brown asked the children what they could do to keep their neighbourhood clean.

19. I asked her how often her school held English speaking contests.

20. Nam's friends asked if his parents would allow him to go camping the next Sunday.

sin78 độ = cos12 độ

sin40 độ = cos 50 độ

sin42 độ = cos 48 độ

Sắp xếp:  sin78 độ  ;  cos24 độ   ;  sin42 độ   ;  sin40 độ   ;  cos87 độ

2. để m đồng biến trên R 

⇔ m - 2 ≥ 0

⇔ m ≥ 2

3.Để m ngịch biến trên R 

⇔ m - 2 ≤ 0

⇔ m ≤ 2

4.gọi điểm cố định có toạ độ ( Xo; Yo) mà đường thẳng y= ( m- 2)x + m - 5 luôn đi qua với mọi m. Thay x= Xo; y=Yo vào hàm số có:

⇔ y= ( m- 2)x + m - 5

⇔ Yo = ( m- 2 )Xo + m - 5

⇔( m- 2 )Xo + m - 5 = Yo

⇔mXo - 2Xo + m - 5 = Yo

⇔ ( mXo + m ) + ( -2Xo - 5 -Yo) = 0

⇔m( Xo+1) + ( -2Xo - 5 -Yo) = 0

Phương trình đúng khi

⇔\(\left\{{}\begin{matrix}Xo+1=0\\-2Xo-5-Yo=0\end{matrix}\right.\)

⇔\(\left\{{}\begin{matrix}Xo=-1\\2-5-Yo=0\end{matrix}\right.\)

⇔\(\left\{{}\begin{matrix}Xo=-1\\Yo=3\end{matrix}\right.\)

5.Để (d) đi qua M ( 2;4) ta thay x=2; y=4 vào h.số có:

4= ( m-2 ) * 2 + m-5

⇔2m - 4 +m -5 = 4

⇔3m=13

⇔ m = 13/3

6. ĐỂ (d) // y= 2x-3 

⇔  \(\left\{{}\begin{matrix}a\ne a'\\b=b'\end{matrix}\right.\)

⇔ \(\left\{{}\begin{matrix}m-2\ne2\\m-5=-3\end{matrix}\right.\)

⇔\(\left\{{}\begin{matrix}m\ne4\\m=2\end{matrix}\right.\)

Vậy m =2 thì (d) // vs đường thẳng

7. Để (d) ⊥ mx+3

⇔ (m-2)m = -1

⇔ 2m - 2m = -1

⇔ 0 = - 1 ( vô lí)

Vậy ko có giá trị nào của m để (d) ⊥ với y = mx+3

6.will leave- gets

7.visited-found-had been

8.have sold - got

9.has worked - decided

10.am told - will find - has never visited

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