1 There is a few water in the bottle

=> There is a little water in the bottle

2 The story is between we house and the movie theater

=> The story is between our house and the movie theater

3 Last summer my parents buyed me a lot of different gifts 

=> Last summer my parents bought me a lot of different gifts 

1. few water => little water

2. we house => our house

3. buyed => bought

HỌC TỐT ^_^

để 3n+4/n-1 là số nguyên

=>3n+4 chia hết cho n-1

ta có: 3n+4=3.(n-1)+7 chia hết cho n-1

mà 3.(n-1) chia hết cho n-1

=>7 chia hết cho n-1

=>n-1 thuộc Ư(7)={-7;-1;1;7}

ta có bảng sau:

vậy n thuộc {-6;0;2;8}

để 3n+4/n-1 là số nguyên

=>3n+4 chia hết cho n-1

ta có: 3n+4=3.(n-1)+7 chia hết cho n-1

mà 3.(n-1) chia hết cho n-1

=>7 chia hết cho n-1

=>n-1 thuộc Ư(7)={-7;-1;1;7}

ta có bảng sau:

vậy n thuộc {-6;0;2;8}

\(A=\frac{2}{1.3}+\frac{2}{3.5}+...+\frac{2}{48.50}\)

\(=1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+...+\frac{1}{48}-\frac{1}{50}\)

\(=1-\frac{1}{50}\)

\(=\frac{50}{50}-\frac{1}{50}\)

\(=\frac{49}{50}\)

Ta có:\(\frac{49}{50}\)và\(\frac{3}{2}\)

Vì\(\frac{49}{50}< 1;\frac{3}{2}>1\)

\(\Rightarrow\frac{49}{50}< \frac{3}{2}\)

Cảm ơn, mình ra vài bài nữa nha mai mình

Mai cô bắt nộp

Điền các từ sau vào chỗ chấm thích hợp để hoàn thành đoạn văn :from ,means,in,waste ,possible ,wind,should,green.However,who .

     Much of our waste ,especailly waste(1)…………from………………..factories,eletric-powered stations ,the chemical industry and heavy industry ,is very dangerous .Fish die (2) ……………in……………..the lakes,riversand seas;forest tree die,too .Much of this dangerous(3) ……………waste……………..goes into the air and is carried by the(4) ………wind…………………..for great distances .

     The Earthis our home.We (5) ……………should……………..take care of it,for ourselves,and for our children and grandchildren .This (6) ………means…………………..we have to keep our environment (7) …………green………………..and clean.The important of this task is pointed out by ecologists-the scientist(8) ………who…………………..study the relations between living things and the environment .(9) ……………However……………..,each of us must do everything (10) ……possible……………………..to keep the land ,air and water clean.

1. do/will improve

2. rains/willnot ride

3. watches/will not be

4. send/ will receive

5. will go/ gets

    1 .If I (do)  do   this test ,I(improve)   will improve   my English.

   2. If it(rain)  rains  tomorrow,I( not ride)  wont't ride  my bike to the mountain.

 3.If she (watch)  watches  a scary filn, she( not be)  won't be  able to sleep

 4.If you ( send)  send  this lette now , she ( receive)  will receive  it tomorrow

 5. Mr Hoa (go)  will go  to london next week if he ( get)   gets  a cheap light

1. We took our Summer holiday visiting Dalat last year.

\(\Rightarrow\)We spent  our Summer holiday visiting Dalat last year.

2. At recess,many students sit and chatting with friends under the shapes of trees.

\(\Rightarrow\)At recess,many students sit and chat with friends under the shapes of trees.

3.  You had better not to touch an electric device with wet hands.

\(\Rightarrow\)You had better not touch an electric device with wet hands.

4.The public library in the city has thousand of good books.

\(\Rightarrow\) The public library in the city has thousands of good books.

1. took => spent

2. chatting => chat

3. to touch => touch

4. thousand => thousands

a) 20,7 + 1,47 : 7 - 0,23 . 5

= 20,7 + 0,21 – 1,15

= 20,91 – 1,15

= 19,76

Ở trên vietjack có đó bn =)

a, 20,7 + 1,47 : 7 - 0,23 . 5

=\(\frac{207}{10}+\frac{147}{100}:7-\frac{23}{100}.5\)

= \(\frac{207}{10}+\frac{21}{100}-\frac{23}{20}\)

= \(\frac{2091}{100}+\frac{-23}{20}\)

= \(\frac{494}{25}\)