Giải cho mình cho mình với sáng mai mình phải nộp bài này rồi

5/7>6/21

18/24>15/25

12/13=1212/1313

\(\dfrac{5}{7}\)>\(\dfrac{6}{21}\)

\(\dfrac{18}{24}\)>\(\dfrac{15}{25}\)

\(\dfrac{12}{13}\)=\(\dfrac{1212}{1313}\)

a) \(\dfrac{12}{14}=\dfrac{1200}{1400}=\dfrac{1400-200}{1400}=1-\dfrac{200}{1400}\)

\(\dfrac{1212}{1414}=\dfrac{1414-200}{1414}=1-\dfrac{200}{1414}\)

vì \(\dfrac{200}{1414}< \dfrac{200}{1400}\)

Nên \(1-\dfrac{200}{1400}< 1-\dfrac{200}{1414}\)

Vậy \(\dfrac{12}{14}< \dfrac{1212}{1414}\)

Các bài sau tương tự

Ta có 1212/1313= 12/13

=> 1212/1313 =12/13

=> 1212/1313 =12/13 

nha bạn

a)Ta có:

\(\frac{1212}{1313}=\frac{12\cdot101}{13\cdot101}=\frac{12}{13}\)

Suy ra \(\frac{12}{13}=\frac{1212}{1313}\)

câu b lạ

a)
Ta có

\(\frac{12}{13}=\frac{12.101}{13.101}=\frac{1212}{1313}\)

\(\Rightarrow\frac{12}{13}=\frac{1212}{1313}\)

b)

Ta có

\(1-\frac{123}{124}=\frac{1}{124}\)

\(1-\frac{124}{125}=\frac{1}{125}\)

Mà  \(\frac{1}{124}>\frac{1}{125}\)

\(\Rightarrow1-\frac{123}{124}>1-\frac{124}{125}\)

\(\Rightarrow\frac{123}{124}< \frac{124}{125}\)

\(\Rightarrow\frac{123}{124}< \frac{124.1001}{125.1001}\)

\(\Rightarrow\frac{123}{124}< \frac{124124}{125125}\)

\(\frac{12}{13}và\frac{1212}{1212}\)

\(\frac{1212}{1313}=\frac{12.101}{13.101}\) \(\Rightarrow\) \(\frac{12}{13}\)

Mà \(\frac{12}{13}=\frac{12}{13}\) \(\Rightarrow\) \(\frac{12}{13}=\frac{1212}{1313}\)

\(\frac{123}{124}\) và \(\frac{124124}{125125}\)

\(1-\frac{123}{124}\) = \(\frac{1}{124}\)

\(1-\frac{124124}{125125}\) = \(\frac{1}{125}\)

Mà \(\frac{1}{124}>\frac{1}{125}\) 

\(\Rightarrow\) \(1-\frac{123}{124}\) > \(1-\frac{124}{125}\)

\(\Rightarrow\) \(\frac{123}{124}\) <\(\frac{124}{125}\) \(\Rightarrow\)  \(\frac{123}{124}\) < \(\frac{124.1001}{125.1001}\)

\(\Rightarrow\) \(\frac{123}{124}< \frac{124124}{125125}\)

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ai giúp mik với mai phải nộp rồi

\(\dfrac{12}{13}\)= \(\dfrac{12.101}{13.101}\)= \(\dfrac{1212}{1313}\) (1)

\(\dfrac{12}{13}\) = \(\dfrac{12.\left(-10101\right)}{13.\left(-10101\right)}\) = \(\dfrac{-121212}{-131313}\)(2)

Từ (1) và (2) => \(\dfrac{12}{13}=\dfrac{1212}{1313}=\dfrac{-121212}{-131313}\)

\(\dfrac{121212}{131313}=\dfrac{121212:10101}{131313:10101}=\dfrac{12}{13}=1-\dfrac{1}{13}\)

\(\dfrac{1313}{1414}=\dfrac{1313:101}{1414:101}=\dfrac{13}{14}=1-\dfrac{1}{14}\)

Vì \(\dfrac{1}{13}>\dfrac{1}{14}\) nên \(\dfrac{12}{13}< \dfrac{13}{14}\) hay \(\dfrac{1212}{1313}< \dfrac{1313}{1414}\)

b) \(\dfrac{1717}{2525}=\dfrac{1717:101}{2525:101}=\dfrac{17}{25}=\dfrac{51}{75}\)

\(\dfrac{515151}{727272}=\dfrac{515151:10101}{727272:10101}=\dfrac{51}{72}\)

Vì \(\dfrac{51}{75}< \dfrac{51}{72}\) nên \(\dfrac{17}{25}< \dfrac{51}{72}\) hay \(\dfrac{1717}{2525}< \dfrac{515151}{727272}\)

a) \(\dfrac{1212}{1313}=\dfrac{101x12}{101x13}=\dfrac{12}{13}< \dfrac{12+1}{13+1}=\dfrac{13}{14}\)

\(\dfrac{1313}{1414}=\dfrac{101x13}{101x14}=\dfrac{13}{14}\)

Vậy \(\dfrac{1212}{1313}< \dfrac{1313}{1414}\)

Làm tương tự câu b

a) 1212/1313 = 12/13 = 1 - 1/13

1313/1414 = 13/14 = 1 - 1/14

Do 13 < 14 nên 1/13 > 1/14

⇒ 1 - 1/13 < 1 - 1/14

Vậy 1212/1313 < 1313/1414

b) 1717/2525 = 17/25

515151/727272 = 51/72 = 17/24

Do 25 > 24 nên 17/25 < 17/24

Vậy 1717/2525 < 515151/727272

Ta có: 22/33 = 2/3 = 12/18

12/19 < 12/18 

Vậy 12/19 < 22/33

\(\frac{1212}{1313}=\frac{101.12}{101.13}=\frac{12}{13}\)

12/13 = 12/13 

Vậy 12/13 = 1212/1313

124124/125125 = \(\frac{1001.124}{1001.125}=\frac{124}{125}\)

1 - 123/124 = 1/124 ; 1 - 124/125 = 1/125

Nên 123/124 < 124/125

Vậy 123/124 < 124124/125125

a) Ta có : 22/33 = 2/3 = 12/18

Vì 12/18 > 12/19 nên 12/19 < 22/33

b) Ta có : 1212/1313 = 12/13

Vì 12/13 = 12/13 nên 12/13 = 1212/1313

c) Ta có : 124124/125125 = 124/125

1 - 123/124 = 1/124

1 - 124/125 = 1/125

Vì 1/124 > 1/125 nên 123/124 < 124124/125125