a) 10  h/s

b) 65 h/s

c) 25 h/s

A)10HS

B)65HS

C)25HS

1. Your friend is drawing a big picture on the wall

    You say: ''Don't draw a big picture pn the wall''

2. Your teacher doesn't want students to make noise in class.

    He/ She say:''The whole class was silent''

3. Mr. Bao doesn't want his son to watch TV all day

    He tells his son:''You should go out''

4. Your mother wants you to help her do housework at weekends

    She say:''Can you help me with housework?"

Chắc chắn đúng!!!

1. Your friend is drawing a big picture on the wall

     You say: '' ... you are so beautiful "..................................... ........................... ''

2. Your teacher doesn't want students to make noise in class.

     He / She say: '' please order "................................. .......................... ''

3. Mr. Doesn't you want his son to watch all day TV

     He told his son: "...... let's go out and play with my friends" ......................... ........................... ''

4. Your mother wants you to help her housework at weekends

     She say: '' ............................................. .......................... ''

Ta có :

\(148:x\)dư 20

\(108:x\)dư 12

\(\Rightarrow148-20⋮x\)

     \(108-12⋮x\)

\(\Rightarrow128⋮x\)

     \(96⋮x\)

\(\Rightarrow x\inƯC\left(96;128\right)\)nhưng \(x\ne1;2\)

\(\Rightarrow x\in\left\{4;8;16;32\right\}\)

\(\frac{2}{3n}=\frac{6}{3\left(n+4\right)}\)

\(\Rightarrow\frac{2.3}{3.3n}=\frac{6}{3\left(n+4\right)}\)

\(\Rightarrow9n=3n+12\)

\(\Rightarrow6n=12\)

\(\Rightarrow n=12:6\)

\(\Rightarrow n=2\)

Còn cách # :)

\(\frac{2}{3n}=\frac{6}{3\left(n+4\right)}\)

\(\Leftrightarrow\frac{2}{3n}=\frac{2}{n+4}\)

<=> 2(n + 4) = 3n.2

<=> 2(n + 4) = 6n

<=> 2n + 8 = 6n

<=> 2n = 6n - 8

<=> 2n - 6n = 6n - 8 - 6n

<=> -4n = -8

<=> n = (-8) : (-4)

<=> n = 2

=> n = 2

   Television first came in the 1950s. Nowadays, it's one of the most(1)_________sources of entertainment for both the old and the young. Television brings(2)___________for children, world news, music and many other(3)____________If someone s sports, he can just choose the right sports(4)______________. It's not difficult for us to see why(5)______________is a TV set in almost every home today

1. A. cheap                        B. expressive                  C.popular                       D. exciting

2. A. news                          B. cartoons                      C. sports                       D. plays

3. A. sets                            B. reports                         C. channels                   D programmes

4. A. athletes                      B. channel                        C. time                           D. studio

5. A. it                                 B. this                                C. that                            D. there     

Làm đại mà chắc đúng

mk ko chắc chắn nhưng cũng giúp bạn

1C

2B

3D

4B

5D

Chúc bạn hc tốt

1. A=> played

2.B => watch

3.B=> bought

4.A=> are

5. B=> take

Find a mistake among the four underlined parts A, B, C or D of each sentence and correct it

1. We play many games at the park yesterday =>1A-play=>played

            A                   B      C                    D

2. Did you watched the show last night?=>2B-watch=>watched

     A                 B        C     D

3. Last summer my parents buyed me a lot of different gifts=>3B-buyed=>bought

                  A                              B               C                          D

4. There was many people standing on the street=>4A-was=>are

                A                   B           C               D

5. Did your uncle took you to watch the football match last week?=>5B-took=>take

     A                         B                C                       D

để phân số trên thuộc Z thì 5 chia hết cho n-3

hay n-3 thuộc ước của 5

hay n-3 thuộc -1;1;-5;5

=> n thuộc 2;4;-2;7

kl:......

Để \(n\in N\)thì \(5⋮n-3\)\

\(\Rightarrow n-3\in\left\{-5;-1;1;5\right\}\)

\(\Rightarrow n\in\left\{-2;2;4;8\right\}\)

c)  \(A=\frac{6}{4}+\frac{6}{28}+\frac{6}{70}+\frac{6}{130}+\frac{6}{208}\) 

\(=\frac{6}{1.4}+\frac{6}{4.7}+\frac{6}{7.10}+\frac{6}{10.13}+\frac{6}{13.16}\) 

\(=2\left(1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+\frac{1}{10}-\frac{1}{13}+\frac{1}{13}-\frac{1}{16}\right)\)

\(=2\left(1-\frac{1}{16}\right)\) 

\(=2.\frac{15}{16}\) 

\(=\frac{15}{8}\) 

Vậy A=\(\frac{15}{8}\)

a) \(\frac{3^2}{1.4}+\frac{3^2}{4.7}+\frac{3^2}{7.10}+...+\frac{3^2}{97.100}\)

\(=3\left(\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}+...+\frac{3}{97.100}\right)\)

\(=3\left(1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+...+\frac{1}{97}-\frac{1}{100}\right)\)

\(=3\left(1-\frac{1}{100}\right)\)

\(=3.\frac{99}{100}=\frac{297}{100}\)