Bài 9:

Đặt f(x) = \(2x^3+ax+b\)

Vì f(x) = \(2x^3+ax+b\) chia cho x + 1 dư 6 và chia cho x - 2 dư 21 nên ta có:

\(\hept{\begin{cases}f\left(-1\right)=2\times\left(-1\right)^3-a+b=6\\f\left(2\right)=2\times2^3+2a+b=21\end{cases}}\)

\(\Leftrightarrow\hept{\begin{cases}-2-a+b=6\\16+2a+b=21\end{cases}}\)

\(\Leftrightarrow\hept{\begin{cases}-a+b=8\\2a+b=5\end{cases}}\)

\(\Leftrightarrow\hept{\begin{cases}-3a=3\\b=5-2a\end{cases}}\)

\(\Leftrightarrow\hept{\begin{cases}a=-1\\b=7\end{cases}}\)

Vậy a = -1, b = 7

Ngố ngây ngô là mình

Mk làm bài 2 nha ><

1. The train will leave at 5:15

2.He is measuring the yard

3. I spent my vacation at the seaside

4. My brother helped me do this exercise

5.Because she has a bad cold

6. They have some bread and butter for lunch

7. They went swimming last Saturday

8. My old teacher will meet me tomorrow

9. Those books are 6 dollars

10. There is one piture on the wall

11. It's 50 meters wide

12. The weather is very hot in June

13. It's about 50 kilometers from here to Vung Tau

14. They went fishing in the river

15. I borrow these books from the library

#Yiin - girl ><

16. They often went to the movies once a month last year

17. I listen folk music

18. They are going to cut grass tomorrowes

19. I think your new dress is nice

20. The performance begins at 6:30

21. He stays in the arcade for about an hour a week

22. I want to see contests programs

#Yiin - girl ><

??? what bài nào cơ?

OoO ToT

https://lazi.vn/uploads/edu/exercise/1505311489_8.jpg

Dễ thây \(\beta=2\alpha\)

Ta co:

\(\left(sin\alpha+cos\alpha\right)^2=sin^2\alpha+cos^2\alpha+2sin\alpha.cos\alpha=1+2sin\left(2\alpha\right)=1+2sin\beta\)

suitable

k mình nha!!!!!!!!!!!

1. to do

nha bạn

to do

to do

1. yesterday, I went  to the retaurant . 

1. yesterday, I wen  to the retaurant . 

WEN VIET SAI ROI