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Để x - 1 là ước của x² - 2x + 3 <=> x² - 2x + 3 ⋮ x - 1

<=> ( x² - 2x + 1 ) + 2 ⋮ x - 1

<=> ( x² - x - x + 1 ) + 2 ⋮ x - 1

<=> [ x(x - 1) - (x - 1) ] + 2 ⋮ x - 1

<=> (x - 1)(x - 1) + 2 ⋮ x - 1 

<=> (x - 1)² + 2  ⋮ x - 1

=> 2 ⋮ x - 1 hay x - 1 là ước của 2 => Ư(2) = { - 2; - 1; 1; 2 }

=> x - 1 = { - 2; - 1; 1; 2 } => x = { - 1; 0 ; 2 ; 3 }

Vậy x = { - 1; 0 ; 2 ; 3 }

Lời giải của bạn Đinh Đức Hùng

Đảm bảo 100% là đúng

Ủng hộ nha

tung yeu nhi

toán này lớp 7 ak. Mình cũng lớp 7 mà sao thấy lạ lạ

Ta có (6a + 1) chia hết cho (3a - 1).

=>(6a + 1) chia hết cho (3a - 1) + (3a - 1)

=>(6a +1) chia hết cho (6a - 2)

=>(6a + 1 + 2 - 2) chia hết cho (6a - 2)

=>(6a - 2 + 3) chia hết cho (6a - 2)

=>3 chia hết cho (6a - 2)

=>(6a - 2) \(\in\)Ư(3) = (1;3)

=>a=\(\varnothing\)

Vậy a=\(\varnothing\)

đúng nhé

6a + 1 chia hết cho 3a - 1

\(\Rightarrow\) 6a - 2 + 3 chia hết cho 3a - 1 

\(\Rightarrow\)2 . ( 3a - 1 ) + 3 chia hết cho 3a - 1

Mà 2 . ( 3a - 1 ) + 3 chia hết cho 3a - 1

\(\Rightarrow\) 3 chia hết cho 3a - 1

\(\Rightarrow\) 3a - 1 \(\in\) Ư(3) = { -3 ; -1 ; 1 ; 3 }

Ta có :

Vậy a = 0 .

I have many hobbies, but I like reading most. Books are always a good friend to me. It is a good way to improve my vocabularies by exposing many new words. By reading, I get better at concentration because it requires me to focus on what I am reading for long periods. It also opens up the knowledge door for me. Reading books tell me about the world's history, let me see the structure of the brain, or bring me a story of Sherlock Holmes. I think reading is one of the most interesting indoors activity.

Bài dịch

Tôi có khá nhiều sở thích nhưng đọc sách là một trong những sở thích mà tôi thấy thú vị nhất và sách luôn là người bạn thân thiết đồng hành cùng tôi. Đọc sách giúp tôi nâng cao vốn từ vựng bởi nó chứa đựng rất nhiều từ mới. Khi đọc tôi nhận được sự tập trung cao độ bởi nó đòi hỏi tôi phải tập trung và những gì tôi đọc trong thơi gian dài. Đọc sách cũng mở ra rất nhiều tri thức mới như tìm hiểu về lịch sử thế giới, biết được cấu trúc của não và biết được câu chuyện về Sherlock Holmes.Tôi nghĩ rằng đọc là một hoạt động trong nhà thú vị nhất đối với tôi

B2:

Health is consisdered the most important to everyone. You can’t do any thing well if you don’t have good health. So how to stay healthy is very important. There are many tips to keep fit, such as:

-do more execrcise

- Eat more fruit and vegetable

- Wash your hand more

- Watch less tv

I think we should try to stay healthy, beside: Live more useful, help orther people, smile more those will make you heathier and happier.

B3:

Volunteering is generally considered an altruistic activity and is intended to promote goodness or improve human quality of life. In return, this activity can produce a feeling of self-worth and respect. There is no financial gain involved for the individual. Volunteering is also renowned for skill development, socialization, and fun. Volunteering may have positive benefits for the volunteer as well as for the person or community served.[1] It is also intended to make contacts for possible employment. It is helping, assisting, or serving another person or persons without pay. Many volunteers are specifically trained in the areas they work, such as medicine, education, or emergency rescue. Others serve on an as-needed basis, such as in response to a natural disaster.

Chúc bn hok tốt ~

Đề 1 :

I have many hobbies, but I like reading most. Books are always a good friend to me. It is a good way to improve my vocabularies by exposing many new words. By reading, I get better at concentration because it requires me to focus on what I am reading for long periods. It also opens up the knowledge door for me. Reading books tell me about the world's history, let me see the structure of the brain, or bring me a story of Sherlock Holmes. I think reading is one of the most interesting indoors activity.

Đề 2 : Văn nói về cách phòng bệnh cúm

I think we need to stay healthy to prevent the flu, keep as healthy as i can by taking good care of myself. Sleep and nutritional considerations are help to prevent the onset of a cold or flu, a healthy lifestyle helps my immune system to be in its best possible shape, giving me the best chance of being able to fight off the onset of a cold or flu. I need to eat healthily. Healthy foods such as vegetables, fruit, grains, etc., are an important part of keeping my body nutrition at its optimum. Processing fatty and sugary foods don't give the immune-boosting protection that healthier food does. Sugary foods can decrease immune function. Exercise regularly. Exercise has enhancing immune-system that can help ward off illness. Overdo too much strenuous or excessive can leave me prone to illness, too. I make sure to get adequate sleep every night, get at least seven to eight hours sleep nightly I need to reduce my stress too. Stress can harm the ability of my immune system to work optimally, and people who are stressed tend to catch colds more than less stressed people. Manage my stress is contributing to prevent the flu. Beside, Drinking water may also help wash cold and flu viruses from my throat to my stomach where they cannot survive. Although getting cold doesn't actually cause a cold or flu (the viruses do), but being cold can reduce my stamina and make me feel miserable and fatigued, so i need to stay warm. In addition, i eat more fruits to get vitamin C that might help me prevent the common cold, and i will also drink more milk, this will be help me healthy and stronger to prevent the cold

Đề 3 :

Volunteering is important for numerous reasons which benefit both the community and the volunteers themselves. When someone donates a handful of time, the difference made is tremendous and it can shape a community for the better while the experience improves the person who have donated the time.

Volunteering is a kind of activity what makes a community because it brings people together to work on a goal. Whether it is a fundraiser for the research to cure a disease affecting the whole world, or to help a local family who has fallen in a time of calamity, volunteers do make it happen. Community life is improved by aiding others and lending a helping hand to get a job done more efficiently. More people working means less work for each person and saving time for the project. So when it comes to getting the job done, like a community clean up, the more the merrier.

When a person donates their time, they give hope to someone who needs it. If a local family’s house burnt down and a group of people hosted a benefit for them, that family’s faith would be revived when they realized that people care for them. Although that family lost their house and their assets, seeing how their own community wants to help would bring them joy and show them that money isn’t everything.

A volunteer also benefits themselves because they get to see how their contribution has made a difference. This experience contributes to personal development especially in some areas such as self-fulfillment, self-confidence, and self-esteem which often flourish in the midst of volunteering experiences. The selfless act of volunteering also provides a spiritual enhancement. Knowing that you made a positive impact on someone is an emotionally uplifting experience that can never be matched by money or fame.

Donating time now will also help in the future. Volunteering strengthens present skills and also shows an employer that an effort has been made to make an improvement. Such skills include communication skills, ability to work with others, ability to take direction and lead others, time management and dedication. Employers will realize that as a volunteer you must be able to prioritize your schedule so as to devote time for activities that benefit others. When employers see active volunteer work on a resume, they are much more likely to employ that person rather than someone who doesn’t do voluntary work. Employers know that most people who offer their time are conscientious, honest and hardworking individuals.

These are just a few reasons why volunteering is important. Not only does it bring hope and happiness to people, but it also leads to spiritual and personal growth. It is an experience that cannot be bought with any amount of money.

abc x 10 + 0 - abc = 2745 (tách theo cấu tạo thập phân)

abc x 10 = 2745 + abc

abc x 9 = 2745 ( cùng bớt abc )

abc = 2745 : 9 

abc = 305

k gúp mik nha

mik học cái này từ lớp 3 rồi

TL:
Ta có:
abc0 + abc =2745
=>abc x10 - abc =2745
=>abc x(10-1)     =2745
=>abc x9            =2745
=>abc                 =2745:9
=>abc                 = 305
Vậy số cần tìm là 305.
HT
 

a) vì 2.3+3 chia hết cho 3 nên n = 3
b) vì 4.2+1=9 là bội của 2.2-1=3 nên n=2
C) vì 4-2=2 là ước của 8.4=32 nên n=4

nếu số đó trừ đi 10% rồi 20% thì số đó bằng 10

Tỉ số phần trăm của 13 và 8 là :

          13 : 8 = 1,625 = 162,5 %

                     Đ/s : 162,5 %

\(\text{Tỉ số phần trăm của 13 và 8 là :}\frac{13}{8}\cdot100=162,5\%\)

Chúc bạn học tốt :>