6 : 31 = 0 dư 6 

?

4³ = 4.4.4 = 64

Em có nhầm đề ko nhỉ lớp 7 ko giải được bài này

\(Sai\) \(Thầy\) \(Ơi\)

a; \(x^3\) + 64 

= \(x^3\) + 4³

= (\(x+4\))(\(x^2\) - 4\(x\) + 16)

b; 2\(x^2\) - 4\(x\)

= 2\(x\)(\(x-2\))

c; 6\(x^2\)y + 4\(xy^2\) + 2\(xy\)

= 2\(xy\)(3\(x\) + 2y + 1)

a) x³ + 64

= x³ + 4³

= (x + 4)(x² − 4x + 16)

b) 2x² − 4x

= 2x(x - 2)

c) 6x²y + 4xy² + 2xy

= 2xy(3x + 2y + 1)

d) Sửa đề: x² − x + y − 2xy + y²

= x² − 2xy + y² − x + y

= (x − y)² − (x − y)

= (x − y)(x − y − 1)

5A:

b: \(47-\dfrac{\left(45\cdot24-5^2\cdot12\right)}{14}\)

\(=47-\dfrac{1080-25\cdot12}{14}\)

\(=47-\dfrac{1080-300}{14}=47-\dfrac{780}{14}=-\dfrac{61}{7}\)

d: \(2345-1000:\left[19-2\left(2\cdot1-18^2\right)\right]\)

\(=2345-1000:\left(19+2\cdot322\right)\)

\(=2345-\dfrac{1000}{19+644}=2345-\dfrac{1000}{663}=\dfrac{1553735}{663}\)

5B:

b: \(50-\left[\left(20-2^3\right)\right]:2+34\)

\(=84-\dfrac{20-8}{2}=84-6=78\)

c: \(20-\left[30-\left(5-1\right)^2\right]:3\)

\(=20-\dfrac{\left[30-4^2\right]}{3}\)

\(=20-\dfrac{14}{3}=\dfrac{46}{3}\)

d: \(205-\left[1200-\left(4^2-23\right)^3\right]:40\)

\(=205-\left[1200-\left(16-23\right)^3\right]:40\)

\(=205-\dfrac{\left[1200-\left(-7\right)^3\right]}{40}\)

\(=205-\dfrac{1200+343}{40}\)

\(=205-38,575=166,425\)

\(u_n=\dfrac{1}{2}\left(\dfrac{2}{1.3}+\dfrac{2}{3.5}+...+\dfrac{2}{\left(2n-1\right)\left(2n+1\right)}\right)\)

\(=\dfrac{1}{2}\left(1-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{5}+...+\dfrac{1}{2n-1}-\dfrac{1}{2n+1}\right)\)

\(=\dfrac{1}{2}\left(1-\dfrac{1}{2n+1}\right)=\dfrac{n}{2n+1}\)

Số hạng thứ \(2021\) là \(u_{2021}=\dfrac{2021}{2.2021+1}=\dfrac{2021}{4043}\)

   68313 - (200 + 313)

= 68313 - 200 -  313 

= (68313 - 313) -  200

= 68000 - 200

= 67800

= 68313 - 313 + 200

= 68000 + 200

= 68200

1. She was not study last night

Sửa: didn't

2. I was study all night for the exam.

Sửa: bỏ was, studied

1. Lỗi: "she was not study last night"  
   Sửa: "She was not studying last night."

2. Lỗi: "I was study all night for the exam"  
   Sửa: "I was studying all night for the exam."

Cả hai lỗi đều là đang hoạt động nhưng không có đuôi ''ing''

      A = 3 + 3² + 3³ + ... + 3²⁰¹⁵

     3A = 3² + 3³ + 3⁴ + ... + 3²⁰¹⁶

3A - A = 3² + 3³ + 3⁴ + ... + 3²⁰¹⁶

    2A    = 3² + 3³ + 3⁴ + ... + 3²⁰¹⁶ - (3 + 3² + 3³ + ... + 3²⁰¹⁵)

    2A =  3² + 3³ + 3⁴ + ... + 3²⁰¹⁶ - 3 - 3² - 3³ - ... - 3²⁰¹⁵

  2 A =  3 ²⁰¹⁶ - 3 + (3² - 3²) + (3³ - 3³) + ... + (3²⁰¹⁵ - 3²⁰¹⁵)

    2A =  3²⁰¹⁶ - 3 + 0 + 0 + ... + 0 + 0

    2A = 3²⁰¹⁶ - 3

2A + 3 = 3²⁰¹⁶ - 3 + 3 

 2A + 3 = 3²⁰¹⁶ - (3 - 3) = 3^4\(x\)

3²⁰¹⁶ = 3^4\(x\)

2016 = 4\(x\)

  \(x\) = 2016 : 4

  \(x=\) 504

Vậy \(x=504\)

1. We will find making models exciting because we be creative.

2. My sister enjoys making new models on her own.

3.My best friend does not like mountain climbing because he is afraid of heights.

4. You need to be patient to make beautiful gifts from eggshells.

5. Playing sports is good for your health.

1 We find making models exciting because we will be creative

2 My sister enjoys making new models on her own

3 My best friend does not like mountain climbing because he is afraid of heights

4 You need to be patienr to make beautiful gifts from eggshells

5 Playing sports is good for your health