Giải thích các bước giải:
Gọi $(4n-9,n+1)=d$
$\to\begin{cases}4n-9\quad\vdots\quad d\\n+1\quad\vdots\quad d\end{cases}$
$\to 4(n+1)-(4n-9)\quad\vdots\quad d$
$\to 13\quad\vdots\quad d$
$\to$Để $\dfrac{4n-9}{n+1}$ tối giản
$\to d=1$
$\to n+1\quad\not\vdots\quad 13$
$\to n+1\ne 13k, k\in Z$
$\to n\ne 13k-1$
Đáp án:
Gọi $UCLN(4n-9;n+1)=d$ \[\to 4(n+1)-(4n-9)\quad\vdots\quad d\] \[\to 13\quad\vdots\quad d\] Để $\dfrac{4n-9}{n+1}$ tối giản $\to d=1$ $\to d\ne 13$ \[\to n+1\ne 13m\] \[\to n\ne 13m-1\]
Tìm GTLN của : M = 5 - |x+2| N = 3 - |2x+4|
Tính :(-57).(75-36)-75.(36-57)= Làm cách giải ko dùng máy tính
Cho tam giác ABC. Trân tia đối của tia BA lấy điểm D sao cho BD=BA . Chứng minh DC vuông góc AC
CHo 1,405g Hỗn hợp gồm Fe2O3, ZnO, MgO tác dụng vừa đủ vs 500ml dd HCl 0.1M .tính khối lượng muối tạo ra trong dd.
câu 1: chất rắn nở khi nào?co lại khi nào câu 2:khi chất rắn nở ra hay co lại khi thì đại lượng nào thay đổi?
Giải hô mình 1000×100÷10×102
I. Choose the best option (A, B, or C) to complete these sentences. 1. Choose the best option (A, B, or C) which has a different sound: A. where B. here C. near 2. We (spoke / speak/ speaks) to our friend last night. 3. (Not/ Do/ Don’t) play football in the street or on the pavement. 4. A person who reports news on TV is a (reporter / film producer / MC) 5. (Where / Who / How often) is your favorite singer? – I like My Tam. 6. Nam gets good marks (but / and / because) he is hard-working. 7. Hoa likes going to the park (and / but / because) Lan likes reading a book at home. 8. ‘Let’s learn’ helps children study Maths. It’s an (educational / popular / entertaining) program. 9. (How many / How much / How long) are you going to spend in Hoi An? – One week. 10. (A weatherman / A comedian / A newsreader) is a person who makes you laugh a lot. 11. We use a (remote control / TV schedule / volume button) to change the channels from a distance. 12. They invite special (character / guests / audiences) to appear in the show. II. Give the correct form of the verbs. 1. The people in the café (not be) friendly when I was there yesterday. 2. I (live) in Danang city five years ago. 3. It (be) a great film in 2001. 4. Our teacher (tell) us to be quiet yesterday. 5. Susan (not know) about the exam and she did very badly. 6. I (buy) a ticket for the football match yesterday. B. READING: Read the passage and do the tasks below: Football is a popular game which keeps players healthy and disciplined. It develops their mind and team spirit and sense of tolerance among them. It is a game played for ninety minutes (in 2 halves of 45 minutes and 15 minutes break). This game has 2 teams of eleven players in each. Players have to kick a ball with their foot and take a goal by putting ball into the goalpost (cột gôn) of the opponent team. In order to oppose the goal made by players of opponent team, there is a goalkeeper on each side. No one player is allowed to touch the ball with hand except the goal-keeper. A team having more goals got declared as the winner and other as closer. The game is conducted (hướng dẫn) by a referee and 2 linesmen (trọng tài biên). All the players are warned to strictly follow the rules while playing this game. It has been an international game and played as World Cup tournament (vòng thi đấu) every four years in different countries worldwide. I. Read the passage and tick () True or False: Questions True False 1. There are 2 teams in the football match. 2. World Cup tournament is held every four years. 3. It is an individual sport. 4. A football match lasts 60 minutes. II. Read the passage again answer the questions: a. Who is allowed to touch the ball with hand? _______________________________________________________ b. Who conductes the game? _______________________________________________________ c. How many halves are there in a football match? _______________________________________________________ C. WRITING: I. Do as directed: 1. I like badminton most. (Rewrite sentence without changing the meaning) My favourite sport________________________________________________ 2. She wasn’t at home. She couldn’t answer the phone. (Rewrite the sentences using SO) __________________________________________________ 3. Mr Hung is my English teacher. (Make questions for the underlined part in the sentence) _________________________________________________________ 4. The weather forecast programme is on VTV1 at 8:30. (Make questions for the underlined part in the sentence) II. Write a short paragraph describe your favourite TV programme (about 50 words). Include this information: The name of the programme The channel it is on The content of programme The reason you like Các bạn giúp mình nhé mình khá yếu TA,mình sẽ vote 5*,thank!
Tìm giá trị của m để phương trình : a/ (m-2)x²+2(2m-3)x+5m-6=0 có hai nghiệm âm phân biệt b/ mx²-2(m+1)x-2m+6=0 có đúng 1 nghiệm c/ mx²-2(m+2)x+2+3m=0 vô nghiệm
Hứa vote 5* cho câu trl đúng nhất ạ ^^
1<|x-2|<4 |x-14+17|+|y+10-12|< hoặc bằng 0 Tìm x , y thuộc Z biết :
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