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Câu hỏi của Nguyen Huong Giang - Toán lớp 7 - Học toán với OnlineMath

cộng thêm 2 vào tính

\(\left(x+y+x\right)\left(x^2+y^2+z^2-xy-xz-yz\right)+3xyz\)

\(=x^3+xy^2+xz^2-x^2y-x^2z-xyz+x^2y+y^3+yz^2-xy^2-xyz-y^2z+x^2z+y^2z+z^3-xyz-xz^2-yz^2+3xyz\)

\(=x^3+0+y^3+z^3\)

\(=x^3+y^3+z^3\)

1. My father waters this flower every morning.

→ This flower is watered (by my father) every morning.

2. John invited Fiona to his birthday party last night.

→ Fiona was invented to John’s birthday party last month.

3. Her mother is preparing the dinner in the kitchen.

→ The dinner is being prepared (by her mother) in the kitchen.

4. We should clean our teeth twice a day.

→ Our teeth should be cleaned twice a day.

5. Our teachers have explained the English grammar.

→ The English grammar has been explained (by our teacher).

6. Some drunk drivers caused the accident in this city.

→ The accident was caused in this city (by some drunk drivers).

7. Tom will visit his parents next month.

→ Tom’s parents will be visited (by him) next month.

8. The manager didn’t phone the secretary this morning.

→ The secretary wasn’t phoned (by the manager) this morning.

9. Did Mary this beautiful dress?

→ Was this beautiful dress bought by Mary?

10. I won’t hang these old pictures in the living room.

→ These old pictures won’t be hung in the living room (by me).

11. The German didn’t build this factory during the Second World War.

→ This factory wasn’t built (by the Greens) during the Second World War.

12. The Greens are going to paint this house and these cars for Christmas Day.

→ This house and these cars are going to be painted for Christmas day by the Greens.

13. Ann had fed the cats before she went to the cinema.

→ The cats had been fed (by Ann) before she went to the cinema.

14. The students have discussed the pollution problems since last week.

→ The pollution problems have been discussed (by the students) since last week.

15. Have the thieves stolen the most valuable painting in the national museum?

→ Has the most valuable painting in the national museum been stolen (by the thieves).

16. Some people will interview the new president on TV.

→ The new president will be interviewed on TV (by some people).

17. How many languages do they speak in Canada?

→ How many languages are spoken in Canada (by them)?

18. Are you going to repair those shoes?

→ Are those shoes going to be repaired?

19. He has broken his nose in a football match.

→ His nose has been broken in a football match (by him).

20. Have you finished the above sentences?

→ Have above sentences been finished?

hơ hơ

bài toán bé ae xé ra to rồi :v