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4 tháng 9 2021

\(7,x^4+x^3+x^2-1=x^3\left(x+1\right)+\left(x-1\right)\left(x+1\right)=\left(x^3+x-1\right)\left(x+1\right)\)

\(8,x^2y^2+1-x^2-y^2=\left(x^2y^2-y^2\right)-\left(x^2-1\right)\\ =y^2\left(x^2-1\right)-\left(x^2-1\right)=\left(x-1\right)\left(x+1\right)\left(y-1\right)\left(y+1\right)\)

\(10,x^4-x^2+2x-1=x^4-\left(x-1\right)^2=\left(x^2-x+1\right)\left(x^2+x-1\right)\\ 11,3a-3b+a^2-2ab+b^2=3\left(a-b\right)+\left(a-b\right)^2=\left(3+a-b\right)\left(a-b\right)\\ 12,a^2+2ab+b^2-2a-2b+1=\left(a+b\right)^2-2\left(a+b\right)+1=\left(a+b-1\right)^2\\ 13,a^2-b^2-4a+4b=\left(a-b\right)\left(a+b\right)-4\left(a-b\right)=\left(a+b-4\right)\left(a-b\right)\\ 14,a^3-b^3-3a+3b=\left(a-b\right)\left(a^2+ab+b^2\right)-3\left(a-b\right)=\left(a-b\right)\left(a^2+ab+b^2-3\right)\\ 15,x^3+3x^2-3x-1=\left(x-1\right)\left(x^2+x+1\right)+3x\left(x-1\right)=\left(x-1\right)\left(x^2+4x+1\right)\)

4 tháng 9 2021

1)
=0,25y.(64x3+z3)
2)
=x2(x2-4x+4)
=x2(x-2)2
5)
=x2(x+1)-4(x+1)
=(x2-4)(x+1)
=(x-2)(x+2)(x+1)
6)
=x2(x-1)-(x-1)
=(x2-1)(x-1)
=(x-1)(x+1)(x-1)
=(x-1)2(x+1)
 

21 tháng 9 2023

Bài 1: - \(\dfrac{5}{7}\) x \(\dfrac{31}{33}\) + \(\dfrac{-5}{7}\) x \(\dfrac{2}{33}\) + 2\(\dfrac{5}{7}\)

         = - \(\dfrac{5}{7}\) \(\times\) ( \(\dfrac{31}{33}\) + \(\dfrac{2}{33}\)) + 2 + \(\dfrac{5}{7}\)

         =  - \(\dfrac{5}{7}\)  + 2 + \(\dfrac{5}{7}\)

          = 2

21 tháng 9 2023

2, \(\dfrac{3}{14}\)\(\dfrac{1}{28}\) - \(\dfrac{13}{21}\)\(\dfrac{1}{28}\) + \(\dfrac{29}{42}\)\(\dfrac{1}{28}\) - 8

   = (\(\dfrac{3}{14}\) - \(\dfrac{13}{21}\) + \(\dfrac{29}{42}\)) : \(\dfrac{1}{28}\) - 8

   =  \(\dfrac{2}{7}\) x 28 - 8

   = 8 - 8

    = 0 

a: \(=\dfrac{-\dfrac{1}{2}\left[cos\left(a+b+a-b\right)-cos\left(a+b-a+b\right)\right]}{cos^2b-cos^2a}\)

\(=\dfrac{-\dfrac{1}{2}\cdot\left[cos2a-cos2b\right]}{\dfrac{1-cos2b}{2}-\dfrac{1-cos2a}{2}}\)

\(=\dfrac{-\dfrac{1}{2}\cdot\left(cos2a-cos2b\right)}{\dfrac{1-cos2b-1+cos2a}{2}}=\dfrac{-\dfrac{1}{2}\cdot\left(cos2a-cos2b\right)}{\dfrac{1}{2}\cdot\left(cos2a-cos2b\right)}=-1\)

c: \(T=\dfrac{sina+sinb\cdot\left(cosa\cdot cosb-sina\cdot sinb\right)}{cosa-sinb\cdot\left(sina\cdot cosb+sinb\cdot cosa\right)}-tan\left(a+b\right)\)

\(=\dfrac{sina+sinb\cdot cosa\cdot cosb-sin^2b\cdot sina}{cosa-sinb\cdot sina\cdot cosb-sin^2b\cdot cosa}-tan\left(a+b\right)\)

\(=\dfrac{sina\left(1-sin^2b\right)+sinb\cdot cosa\cdot cosb}{cosa\left(1-sin^2b\right)-sinb\cdot sina\cdot cosb}\)-tan(a+b)

\(=\dfrac{sina\cdot cos^2b+sinb\cdot cosa\cdot cosb}{cosa\cdot cos^2b-sinb\cdot sina\cdot cosb}-tan\left(a+b\right)\)

\(=\dfrac{sina\cdot cosb+sinb\cdot cosa}{cosa\cdot cosb-sina\cdot sinb}-tan\left(a+b\right)\)

\(=\dfrac{sin\left(a+b\right)}{cos\left(a+b\right)}-tan\left(a+b\right)=0\)

 

NV
4 tháng 3 2022

4.

\(\lim\limits_{x\rightarrow8}f\left(x\right)=\lim\limits_{x\rightarrow8}\dfrac{\sqrt[3]{x}-2}{x-8}=\lim\limits_{x\rightarrow8}\dfrac{x-8}{\left(x-8\right)\left(\sqrt[3]{x^2}+2\sqrt[3]{x}+4\right)}=\lim\limits_{x\rightarrow8}\dfrac{1}{\sqrt[3]{x^2}+2\sqrt[3]{x}+4}\)

\(=\dfrac{1}{4+4+4}=\dfrac{1}{12}\)

\(f\left(8\right)=3.8-20=4\)

\(\Rightarrow\lim\limits_{x\rightarrow8}f\left(x\right)\ne f\left(8\right)\)

\(\Rightarrow\) Hàm gián đoạn tại \(x=8\)

5.

\(\lim\limits_{x\rightarrow0^+}f\left(x\right)=\lim\limits_{x\rightarrow0^+}\dfrac{\sqrt[]{1+2x}-1+1-\sqrt[3]{1+3x}}{x}=\lim\limits_{x\rightarrow0^+}\dfrac{\dfrac{2x}{\sqrt[]{1+2x}+1}-\dfrac{3x}{1+\sqrt[3]{1+3x}+\sqrt[3]{\left(1+3x\right)^2}}}{x}\)

\(=\lim\limits_{x\rightarrow0^+}\left(\dfrac{2}{\sqrt[]{1+2x}+1}-\dfrac{3}{1+\sqrt[3]{1+3x}+\sqrt[3]{\left(1+3x\right)^2}}\right)=\dfrac{2}{1+1}-\dfrac{3}{1+1+1}=0\)

\(f\left(0\right)=\lim\limits_{x\rightarrow0^-}f\left(x\right)=\lim\limits_{x\rightarrow0^-}\left(3x^2-2x\right)=0\)

\(\Rightarrow\lim\limits_{x\rightarrow0^+}f\left(x\right)=\lim\limits_{x\rightarrow0^-}f\left(x\right)=f\left(0\right)\)

\(\Rightarrow\) Hàm liên tục tại \(x=0\)

NV
4 tháng 3 2022

6.

\(\lim\limits_{x\rightarrow0^+}f\left(x\right)=\lim\limits_{x\rightarrow0^+}\dfrac{\sqrt[]{4x+1}-\sqrt[3]{6x+1}}{x^2}\)

\(=\lim\limits_{x\rightarrow0^+}\dfrac{\sqrt[]{4x+1}-\left(2x+1\right)+\left(2x+1-\sqrt[3]{6x+1}\right)}{x^2}\)

\(=\lim\limits_{x\rightarrow0^+}\dfrac{\dfrac{-x^2}{\sqrt[]{4x+1}+2x+1}+\dfrac{x^2\left(8x+12\right)}{\left(2x+1\right)^2+\left(2x+1\right)\sqrt[3]{6x+1}+\sqrt[3]{\left(6x+1\right)^2}}}{x^2}\)

\(=\lim\limits_{x\rightarrow0^+}\left(\dfrac{-1}{\sqrt[]{4x+1}+2x+1}+\dfrac{8x+12}{\left(2x+1\right)^2+\left(2x+1\right)\sqrt[3]{6x+1}+\sqrt[3]{\left(6x+1\right)^2}}\right)\)

\(=\dfrac{-1}{1+1}+\dfrac{12}{1+1+1}=\dfrac{7}{2}\)

\(f\left(0\right)=\lim\limits_{x\rightarrow0^-}f\left(x\right)=\lim\limits_{x\rightarrow0^-}\left(2-3x\right)=2\)

\(\Rightarrow\lim\limits_{x\rightarrow0^+}f\left(x\right)\ne\lim\limits_{x\rightarrow0^-}f\left(x\right)\)

\(\Rightarrow\) Hàm gián đoạn tại \(x=0\)

25 tháng 1 2022

a) \(\left(-23\right)+230+23=0+230=230.\)

b) \(124.\left(-54\right)+24.54=54.\left(-124+24\right)=54.\left(-100\right)=-5400.\)

c) \(-927+1421+930+\left(-1421\right).\)

\(=-927+930=3.\)

 

25 tháng 1 2022

a) (-23) + 230 + 23 =230

b) 124 . (-54) + 24 . 54 = 5400.

c) -927 + 1421 + 930 + (-1421) =3.

d) (-351) + (-74) + 51 + (-126) + 149=-351

Mn giúp mik ak câu nào mn bt thì lm còn lm hết đc thì càng tốt nhé TKS10. ……………. festival do you choose? - I choose Elephant Race Festival.A. What B. How C. Which D. When11. ……………. often is Burning Festival held? - It's held every year.A. Which B. When C. What D. How12. ……………. does the teacher say La Tomatina sounds unusual? - Because people throw tomatoes at each other for one hour at the festival.A. What B. When C. Why D. How13. He ___________ books for poor children for years.A. has...
Đọc tiếp

Mn giúp mik ak câu nào mn bt thì lm còn lm hết đc thì càng tốt nhé TKS

10. ……………. festival do you choose? - I choose Elephant Race Festival.

A. What B. How C. Which D. When

11. ……………. often is Burning Festival held? - It's held every year.

A. Which B. When C. What D. How

12. ……………. does the teacher say La Tomatina sounds unusual? - Because people throw tomatoes at each other for one hour at the festival.

A. What B. When C. Why D. How

13. He ___________ books for poor children for years.

A. has collected B. collects C. is collecting D. collected

14. Next Saturday at this time, we _____ on the beach in Mexico.

A. will relax B. will be relaxing C. has relaxed D. relax

15. Anne and Joe _____ by sea tomorrow

A. travel B. will travel C. travels D. travelled

16. I_____ in Jakarta, but now I live in New York. [use to + V-inf]

A. used to living B. used to living C. used to live D. am used to live

17. Jane_____ for the telephone company, but now she has a job at the post office.

A. used to working B. used to worked C. is used to work D. used to work

18. …………. he spent much money on the film, it wasn't a big success.

A. Even B. But C. Although D. Despite

19. We didn't find it funny………..it was a comedy.

A. in spite of B. despite C. although D. but

20. I went to the cinema with my friends yesterday ………… feeling very tired.

A. although B. in spite C. despite D. but

21. Let's go to the Victor Cinema. I'm sure you'll find the film…………

A. excites B. excite C. excited D. exciting

22. I was ……… to learn that the director of that gripping film has won the first prize.

A. interest B. interests C. interested D. interesting

23. The film was boring, ____ we went home.

A. so B. when C. but D. if

24. Nam was absent from class yesterday ____ he felt sick.

A. so B. because C. although D. but

25. These books aren’t yours, ____________?

A.are these B. aren’t these C. are they D. aren’t they

26. No one died in the accident, ______________?

A.did they B. didn’t they C. did he D. didn’t he

27. Tom knows Alice, _____________?

A.doesn’t he B. is he C. does he D. isn’t he

28. Peter never comes to class late, ________________?

A. doesn’t he B. doesn’t Peter C. does he D. does Peter

29. ……… computer is a laptop, but ……… is a desktop.

A. Hers - you B. Her - your C. My - yours D. Mine - yours

30. We gave them ……… ID number, and they gave us ……….

A. ours - theirs B. our - theirs C. our -their D. ours - their

2
3 tháng 8 2021

10. ……………. festival do you choose? - I choose Elephant Race Festival.

A. What B. How C. Which D. When

11. ……………. often is Burning Festival held? - It's held every year.

A. Which B. When C. What D. How

12. ……………. does the teacher say La Tomatina sounds unusual? - Because people throw tomatoes at each other for one hour at the festival.

A. What B. When C. Why D. How

13. He ___________ books for poor children for years.

A. has collected B. collects C. is collecting D. collected

14. Next Saturday at this time, we _____ on the beach in Mexico.

A. will relax B. will be relaxing C. has relaxed D. relax

15. Anne and Joe _____ by sea tomorrow

A. travel B. will travel C. travels D. travelled

16. I_____ in Jakarta, but now I live in New York. [use to + V-inf]

A. used to living B. used to living C. used to live D. am used to live

17. Jane_____ for the telephone company, but now she has a job at the post office.

A. used to working B. used to worked C. is used to work D. used to work

18. …………. he spent much money on the film, it wasn't a big success.

A. Even B. But C. Although D. Despite

19. We didn't find it funny………..it was a comedy.

A. in spite of B. despite C. although D. but

20. I went to the cinema with my friends yesterday ………… feeling very tired.

A. although B. in spite C. despite D. but

21. Let's go to the Victor Cinema. I'm sure you'll find the film…………

A. excites B. excite C. excited D. exciting

22. I was ……… to learn that the director of that gripping film has won the first prize.

A. interest B. interests C. interested D. interesting

23. The film was boring, ____ we went home.

A. so B. when C. but D. if

24. Nam was absent from class yesterday ____ he felt sick.

A. so B. because C. although D. but

25. These books aren’t yours, ____________?

A.are these B. aren’t these C. are they D. aren’t they

26. No one died in the accident, ______________?

A.did they B. didn’t they C. did he D. didn’t he

27. Tom knows Alice, _____________?

A.doesn’t he B. is he C. does he D. isn’t he

28. Peter never comes to class late, ________________?

A. doesn’t he B. doesn’t Peter C. does he D. does Peter

29. ……… computer is a laptop, but ……… is a desktop.

A. Hers - you B. Her - your C. My - yours D. Mine - yours

30. We gave them ……… ID number, and they gave us ……….

A. ours - theirs B. our - theirs C. our -their D. ours - their

3 tháng 8 2021

Mn giúp mik ak câu nào mn bt thì lm còn lm hết đc thì càng tốt nhé TKS

10. ……………. festival do you choose? - I choose Elephant Race Festival.

A. What B. How C. Which D. When

11. ……………. often is Burning Festival held? - It's held every year.

A. Which B. When C. What D. How

12. ……………. does the teacher say La Tomatina sounds unusual? - Because people throw tomatoes at each other for one hour at the festival.

A. What B. When C. Why D. How

13. He ___________ books for poor children for years.

A. has collected B. collects C. is collecting D. collected

14. Next Saturday at this time, we _____ on the beach in Mexico.

A. will relax B. will be relaxing C. has relaxed D. relax

15. Anne and Joe _____ by sea tomorrow

A. travel B. will travel C. travels D. travelled

16. I_____ in Jakarta, but now I live in New York. [use to + V-inf]

A. used to living B. used to living C. used to live D. am used to live

17. Jane_____ for the telephone company, but now she has a job at the post office.

A. used to working B. used to worked C. is used to work D. used to work

18. …………. he spent much money on the film, it wasn't a big success.

A. Even B. But C. Although D. Despite

19. We didn't find it funny………..it was a comedy.

A. in spite of B. despite C. although D. but

20. I went to the cinema with my friends yesterday ………… feeling very tired.

A. although B. in spite C. despite D. but

21. Let's go to the Victor Cinema. I'm sure you'll find the film…………

A. excites B. excite C. excited D. exciting

22. I was ……… to learn that the director of that gripping film has won the first prize.

A. interest B. interests C. interested D. interesting

23. The film was boring, ____ we went home.

A. so B. when C. but D. if

24. Nam was absent from class yesterday ____ he felt sick.

A. so B. because C. although D. but

25. These books aren’t yours, ____________?

A.are these B. aren’t these C. are they D. aren’t they

26. No one died in the accident, ______________?

A.did they B. didn’t they C. did he D. didn’t he

27. Tom knows Alice, _____________?

A.doesn’t he B. is he C. does he D. isn’t he

28. Peter never comes to class late, ________________?

A. doesn’t he B. doesn’t Peter C. does he D. does Peter

29. ……… computer is a laptop, but ……… is a desktop.

A. Hers - you B. Her - your C. My - yours D. Mine - yours

30. We gave them ……… ID number, and they gave us ……….

 

A. ours - theirs B. our - theirs C. our -their D. ours - their

 

28 tháng 12 2020

Vào phần hộp thư đi mik sẽ gửi đáp ná cho bạn 🙂

29 tháng 12 2020

Câu 1:

     Thành phần chủ yếu của tế bào thực vật:

     – Vách tế bào (chỉ có ở tế bào thực vật): quy định và duy trì hình dạng tế bào.

     – Màng sinh chất: bao bọc bên ngoài chất tế bào.

     – Chất tế bào: dạng keo lỏng, bên trong chứa các bào quan (lục lạp, không bào, ribôxôm, …).

     – Nhân: điều khiển hoạt động sống của tế bào.

9 tháng 12 2021

dài thế =))

9 tháng 12 2021

câu 8 trên bài 3 thui ạ

 

AH
Akai Haruma
Giáo viên
9 tháng 9 2023

Với số to như 25764 bạn muốn kiểm tra có chia hết cho 8 không thì có thể lấy 3 chữ số cuối cùng. Nếu 3 chữ số cuối cùng tạo thành số chia hết cho 8 thì cả số đó chia hết cho 8 còn không thì không chia hết.

Trong TH này 764 không chia hết cho 8 nên 25764 cũng không chia hết cho 8.