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B7 chu vi mảnh vườn là 3,3 m

diện tích là \(\dfrac{8}{7}\)m vuông

Bài 7:

Chu vi là:

\(\left(\dfrac{12}{5}+\dfrac{10}{21}\right)\cdot2=\dfrac{604}{105}\left(m\right)\)

Diện tích là:

\(\dfrac{12}{5}\cdot\dfrac{10}{21}=\dfrac{8}{7}\left(m^2\right)\)

B8 chu vi hình thoi là 20,8 m

diện tich hinh thoi là 22,8 m vuông 

tick cho mk

4 has not been - broke

5 did you - was

6 have youy ever been

II

1 go

2 were

3 eats

7 does - won't worry

8 had played - would have won

9 will - do

10 were - would go

14 would have written

15 won't go

16 tries

17 spoke

19 finish - will go

20 see - ask

Rewrite

1 The man who doesn't work hard can't earn more money

3 If my friend and I had enough money, we would buy a  house of our town

4 If the weather were better now, we could go for a walk

5 If I knew his addres, I would give it to you

6 If he worked slowly enough, he wouldn't make

7 If I were sent to proson, she would visit me 

8 If I won a big prize in a lottery, I would give up my job

9 If the doctor weren't so late, he could see many patients

10 If tickets weren't expensive, we would visit them in Ha Noi

III

1 were

2 would visit

3 would give

I have been sleeping for 3 minutes

Tôi đã ngủ được 3 tiếng rồi

S+have been+Ving => làm gì đó được bao lâu/từ lúc nào

Bài 4:

\(P=\dfrac{x^2-2x+2022}{x^2}=\dfrac{2022x^2-2.2022x+2022^2}{2022x^2}=\dfrac{\left(x^2-2.2022x+2022^2\right)+2021x^2}{2022x^2}=\dfrac{\left(x-2022\right)^2}{2022x^2}+\dfrac{2021}{2022}\ge\dfrac{2021}{2022}\)\(P_{min}=\dfrac{2021}{2022}\Leftrightarrow x=2022\)

Đề bị lỗi hiển thị rồi bạn.

A = 0,5 + 1 + 1,5 + 2 + ... + 10

Số số hạng của dãy số A :

( 10 - 0,5 ) : 0,5 + 1 = 20 (số hạng)

Tổng của dãy số A là :

( 10 + 0,5 ) x 20 : 2 = 105

=))

A= (0,5+1,5)+(1+9)+(2+8)+(3+7)+(4+6)+(5+10)

A= 2+10+10+10+10+15

A= 12+10+10+10+15

A= 22+10+10+15

A= 32+10+15

A= 42+15

A= 57