#\(yGLinh\)

Vì bạn chụp ảnh nhìn mờ quá nên mình khó có thể giúp bạn, bạn tham khảo [chọn lọc] bảng cách chia s/es trên nhé ạ!

Mình cảm ơn bạn!

\(#BadGirl\)

10 câu với chủ ngữ để động từ không chia:

- They have lunch at school.

- We have breakfast at home.

- Sometimes we need to go to the doctor.

- I go to school every Mondays.

- I don't have to go to school on Sundays.

- We have to do this homework!

- Do you like this game?

- They always sleep at 10 p.m.

- You need to do your homework!

- My friends usually talk about their future.

\(#BadGirl\)

10 câu với chủ ngữ để động từ phải chia:

- She always plays the piano.

- She sometimes reads a book.

- He is cleaning the floor now.

- He is cooking in the kitchen now.

- She never plays the guitar.

- She loves playing with dogs.

- He is playing football.

- My mother is reading the news.

- My dad is listening to the radio.

- My sister is chatting with friends on the computer.

\(#BadGirl\)

1. learn

2. goes

3. feel

4. study

5. have

6. does

7. likes

8. What time do you have

9. doesn't have

 1 They (learn) _ how to use the lawnomuwer in the gaden-> learn

 2 Linda (go) _ to the supermarket to buy some sugar

->goes

 3 Sometimes I (feel) _ really lazy to do anything

->feel

 4 Phong and I (study) _ English in my room

-> study

 5 I often (have) breakfast at 7 a.m at home

->have

 6 She (do) _ aerobics every morning to keep fit

->does

 7 Nga (like) _ plaing basketball very much

->likes

 8 What time you (have) _ lunch everyday ?

->do you have

 9 She (not have) _ any pen , so do I lend her one

->doesn't have

\(1+\dfrac{3}{2}+2+\dfrac{5}{2}+...+\dfrac{199}{2}+100\)

\(=\dfrac{2}{2}+\dfrac{3}{2}+\dfrac{4}{2}+...+\dfrac{200}{2}\)

\(=\dfrac{2+3+4+...+200}{2}\)

\(=\dfrac{199\cdot\dfrac{\left(200+2\right)}{2}}{2}=199\cdot\dfrac{202}{4}=10049,5\)

\(1+\dfrac{3}{2}+2+\dfrac{5}{2}+...+\dfrac{199}{2}+100\)

\(=\dfrac{2}{2}+\dfrac{3}{2}+\dfrac{4}{2}+\dfrac{5}{2}+...+\dfrac{199}{2}+\dfrac{200}{2}\)

\(=\dfrac{2+3+4+5+...+199+200}{2}\)

Số số hạng của \(2+3+4+5+..+199+200\) là :

\(\left(200-2\right):1+1=199\)

Tổng là :

\(\left(200+2\right)\times199:2=20099\)

Ta có :

\(\dfrac{20099}{2}\) \(=10049,5\)

Lời giải:

Ta thấy, với $a,b,c,d>0$ thì:

$\frac{a}{a+b+c}+\frac{b}{b+c+d}+\frac{c}{c+d+a}+\frac{d}{d+a+b}> \frac{a}{a+b+c+d}+\frac{b}{a+b+c+d}+\frac{c}{a+b+c+d}+\frac{d}{a+b+c+d}=\frac{a+b+c+d}{a+b+c+d}=1(*)$

Lại có:

Xét $\frac{a}{a+b+c}-\frac{a+d}{a+b+c+d}=\frac{-d(b+c)}{(a+b+c)(a+b+c+d)}<0$ với mọi $a,b,c,d>0$

$\Rightarrow \frac{a}{a+b+c}< \frac{a+d}{a+b+c+d}$

Tương tự: $\frac{b}{b+c+d}< \frac{b+a}{a+b+c+d}, \frac{c}{c+d+a}< \frac{c+b}{a+b+c+d}; \frac{d}{d+a+b}< \frac{d+c}{a+b+c+d}$

Cộng lại suy ra:

$\frac{a}{a+b+c}+\frac{b}{b+c+d}+\frac{c}{c+d+a}+\frac{d}{d+a+b}< \frac{a+d+b+a+c+b+d+c}{a+b+c+d}=\frac{2(a+b+c+d)}{a+b+c+d}=2(**)$

Từ $(*); (**)\Rightarrow$ đpcm.

11: \(2^2\cdot3^2-5\cdot2\cdot3=6^2-30=36-30=6\)

12: \(3^2\cdot5-2^2\cdot7+1\cdot5=9\cdot5-4\cdot7+5\)

=45-28+5

=50-28=22

13: \(5^2\cdot2-3^2\cdot4=25\cdot2-9\cdot4=50-36=14\)

14: \(7^2\cdot3-5^2\cdot3=49\cdot3-25\cdot3=24\cdot3=72\)

15: \(2^3\cdot3^2-4^2\cdot3=8\cdot9-16\cdot3=72-48=24\)

16: \(5^2\cdot2^3+3^2\cdot7-8^2\cdot2\)

\(=25\cdot8+9\cdot7-64\cdot2\)

=200+63-128

=263-128=135

17: \(\left(5\cdot2^2-20\right):5+3^2\cdot6=\left(5\cdot4-20\right):5+9\cdot6\)

=0+54

=54

18: \(\left(24\cdot5-5^2\cdot2\right):\left(5\cdot2\right)-3\)

\(=\left(120-50\right):10-3\)

=7-3=4

19: \(\left[\left(5^2\cdot2^3-7^2\cdot2\right):2\right]\cdot6-7\cdot2^5\)

\(=\left[5^2\cdot2^2-7^2\right]\cdot6-7\cdot32\)

=(100-49)*6-224

=51*6-224

=82

20: \(\left(6\cdot5^2-13\cdot7\right)\cdot2-2^3\left(7+3\right)\)

\(=\left(6\cdot25-91\right)\cdot2-8\cdot10\)

\(=\left(150-91\right)\cdot2-80\)

=118-80=38

$a(b-c)-a(b+d)$

$=ab-ac-ab-ad$

$=-ac-ad$

\(a\left(b-c\right)-a\left(b+d\right)\\ =a\left[\left(b-c\right)-\left(b+d\right)\right]\\ =a\left(b-c-b+d\right)\\ =a\left(d-c\right)\)

\(6\left(x\cdot3\right)\)

\(=6\cdot3x\)

\(=18x\)

=73.8-73.59 - 59.8 + 59.73

=584 - 4307 - 472 + 4307

=-7323 + 3835

=-3488

$73.(8-59)-59.(8-73)$

$=73.8-73.59-59.8+59.73$

$=73.8-59.8$

$=8.(73-59)$

$=8.14=112$

8= 2³ ; 27 = 3³ ; 125= 5³ ; 216 = 6³ ; 343 = 7³ ; 8000 = 20³