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Dear truong trang

I'm pleased to hear that you and your family are well. Now I write this letter to tell you about my study ay school. I received my first semester report last week. I got good grades for Science, English and History, but my math result was poor. My math teacher asked me to spend more time on it. I must study harder next semester in order to improve it.
How about you ? Please write soon and tell me all your news. I'm looking foward to seeing your letter.
Regards,
tran si anh quoc

a) 3 chia hết cho n-1

=> 3 : (n - 1) = 1

     n - 1 = 3 : 1 = 3

     n = 3 + 1 = 4

=> n\(\in\)Ư (4) = {-4; -2; -1; 1; 2; 4}

b) Ta có: n + 3 = n + 1 + 2

Mà n + 3 chia hết cho n+1

=> n + 1 + 2 chia hết cho n + 1

=> 2 chia hết cho n + 1

=> n + 1\(\in\)Ư (2) = {-2; -1; 1; 2}

=> n\(\in\){-3; -2; 0; 1}

My favourite leisure activity is reading. I like reading because it is a hobby that is useful and interesting: useful because you can find a lot of knowledge of all areas that you need; interesting because the books can give you the joy and help you relax after a day of toil etc... Especially, when you join the forum, you can meet a lot of people who have interests similar to yours, comment on the books or novels that interest you.

I love books and also natural as reading books. At the age of ten, I was awarded "The Scarlet Sails" of Alexandre Green by my grandfather. It is the first of book that I have been. I read it does not know how many times (Up to now, I still love it and occasionally read it again). My love for books begun.

I usually spend almost of free time in choosing the book with my friends, participate in dicussion on the forum and reading (of course!). Every weekend and all holidays when I have no work to do, I often read books and ruminate on it. I also help some friends can select the genres of books that they like.

I always hope that I will have my own library in my future. I love books very much and perhaps, I couldn't live without them.