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Trần Nam Khánh
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Nguyễn Lê Phước Thịnh
5 tháng 8 2021 lúc 23:19

Bài 3: 

2) Ta có: \(B=2x\left(y-z\right)+\left(z-y\right)\left(x+t\right)\)

\(=2x\left(y-z\right)-\left(x+t\right)\left(y-z\right)\)

\(=\left(y-z\right)\left(x-t\right)\)

\(=\left(24-10,6\right)\left(18,3+31,7\right)\)

\(=13,4\cdot50=670\)

3) Ta có: \(C=\left(x-y\right)\left(y+z\right)+y\left(y-x\right)\)

\(=\left(x-y\right)\left(y+z\right)-y\left(x-y\right)\)

\(=z\left(x-y\right)\)

\(=1.5\left(0.86-0.26\right)\)

\(=0,9\)

Trân Trần
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Lấp La Lấp Lánh
20 tháng 10 2021 lúc 17:46

Đề sai r bạn, MN vừa bằng 8cm vừa bằng 50mm?

Vy Thùy
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Minh Nhân
20 tháng 1 2022 lúc 19:12

\(\dfrac{10+10+10+10+9.75\cdot2+9.33\cdot3}{9}=9.7\)

danny danh
20 tháng 1 2022 lúc 19:12

8.18 nha bạn

๖ۣۜHả๖ۣۜI
20 tháng 1 2022 lúc 19:13

10 + 10 + 10 + 10 + 10 + 9,75+ 9,75 + 9,33 + 9,33 + 9,33 / 10 = 9,7

LUFFY WANO
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Nguyễn Đức Trí
6 tháng 9 2023 lúc 21:15

1.she spends 20 minutes to draw a picture

2.Lan is the most creative in the group

3.No one is smaller than him

4.My pen isn't the same than mine

5.Lan is jealous than her

6.My brother no longer raise pets

-chúc bạn thật thông minh!!!!

Trinhdiem
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ILoveMath
19 tháng 12 2021 lúc 20:32

\(\dfrac{x^3-8}{x+7}\left(\dfrac{3}{x-2}-\dfrac{2}{x^2+2x+4}\right)\\ =\dfrac{\left(x-2\right)\left(x^2+2x+4\right)}{x+7}\left(\dfrac{3\left(x^2+2x+4\right)}{\left(x-2\right)\left(x^2+2x+4\right)}-\dfrac{2\left(x-2\right)}{\left(x-2\right)\left(x^2+2x+4\right)}\right)\\ =\dfrac{\left(x-2\right)\left(x^2+2x+4\right)}{x+7}\left(\dfrac{3x^2+6x+12}{\left(x-2\right)\left(x^2+2x+4\right)}-\dfrac{2x-4}{\left(x-2\right)\left(x^2+2x+4\right)}\right)\)

\(=\dfrac{\left(x-2\right)\left(x^2+2x+4\right)}{x+7}.\dfrac{3x^2+6x+12-2x+4}{\left(x-2\right)\left(x^2+2x+4\right)}\)

\(=\dfrac{3x^2+4x+16}{x+7}\)

Nguyễn Lê Phước Thịnh
19 tháng 12 2021 lúc 20:31

\(=\dfrac{\left(x-2\right)\left(x^2+2x+4\right)}{x+7}\cdot\dfrac{3x^2+6x+12-2x+4}{\left(x-2\right)\left(x^2+2x+4\right)}\)

\(=\dfrac{3x^2+4x+16}{x+7}\)

Nguyễn Minh Đạt
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NeverGiveUp
27 tháng 6 lúc 21:04

1.I think you ought to give up playing video games. (should)

-->I think you should give up playing video games.

2.It's necessary for me to finish the work on time. (have to)

--->I have to finish the work on time.

3.It wasn't necessary for you to clean that car. (have to)

--->You didn't have to clean that car.

4.It was quite unnecessary for you to adopt a green lifestyle. (have to)

---->You didn't have to adopt a green lifestyle.

5.It was careless of you to leave the windows open last night. (shouldn't)

----->You shouldn't have left the windows open last night.

6.It is advisable for each member in the family to share the housework equally. (should)

---->Each member in the family should share the housework equally.

7.You are required to come back home before 10 p.m. (must)

--->You must come back home before 10 p.m.

8.Lina is advised to prepare carefully in the morning. (should)

----->Lina should prepare carefully in the morning.

9.Tu is responsible for picking up litter. (have to)

------>Tu has to pick up litter.

NeverGiveUp
27 tháng 6 lúc 21:07

1.You are required to ask your parents for permission before staying out late. (must)

You must ask your parents for permission before staying out late.

2.I think you ought to give up smoking immediately. (should)

I think you should give up smoking immediately.

3.It is not a good idea for me to stay up late. (shouldn't)

I shouldn't stay up late.

4.It wasn't necessary for you to send these letters. (have to)

You didn't have to send these letters.

5.It was unnecessary for Tim to finish the work. (have to)

Tim didn't have to finish the work.

6.It was careless of you to leave your children alone at home. (shouldn't)

You shouldn't have left your children alone at home.

Bằng 1 cách nào đó 1 câu hỏi từ 2023 ở đây và tôi vẫn trả lời nó sau 1 năm :v

Nguyễn Minh Đạt
12 tháng 11 2023 lúc 20:29

loading...  

Trân Trần
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le thai
20 tháng 10 2021 lúc 18:10

NA=AB/2=7/2=3.5cm

꧁༺ǤᎥᗩᑎǤ༻꧂
20 tháng 10 2021 lúc 18:31

Đoạn thẳng NA dài là:   7 : 2 = 3,5(cm)

 

Nguyễn Minh Sơn
22 tháng 10 2021 lúc 8:49

3,5 cm

Trinhdiem
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34 Ngọc Trâm
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yến nhi
2 tháng 3 2022 lúc 10:41

1 The distance  from my home to  school is about 3 km

2 My mum used to live in a small village when she was small
3 Despite being a millionaire , he lives in a small flat 
4 when does the festive take place ?
5 It is about two kilometres from my home to school
6 he didn't use to ride his bike to school 
7 Despite having a test tomrrow , they are still watching TV now 

kocoten127
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Nguyễn Lê Phước Thịnh
31 tháng 10 2021 lúc 0:00

a: Xét ΔBAC có 

D là trung điểm của AB

M là trung điểm của AC

Do đó: DM là đường trung bình của ΔABC

Suy ra: DM//BC và \(DM=\dfrac{BC}{2}=3.5\left(cm\right)\)