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1.a) 3/4 > 5/10

   b) 35/25 > 16/14

2.a) 7/5 > 5/7

  b) 14/16 < 24/21

HT nha

( bạn t.i.c.k cho mik nha, mik cảm ơn )

Tyyyyn

Bạn giúp mình câu này nhé so sánh 317/633 và 371/743 

8⁵ = (2³)⁵ = 2¹⁵ = 2.2¹⁴

3.4⁷ = 3.(2²)⁷ = 3.2¹⁴

Do 2 < 3 nên 2.2¹⁴ < 3.2¹⁴

Vậy 8⁵ < 3.4⁷

\(8^5=2^{15}=2.2^{14}\)

\(3.4^7=3.2^{14}>2.2^{14}\)

\(\Rightarrow8^5< 3.4^7\)

a)

\(\dfrac{48}{92}=\dfrac{48:4}{92:4}=\dfrac{12}{23}\)
\(\dfrac{36}{69}=\dfrac{36:3}{69:3}=\dfrac{12}{23}\)
Ta có: 
Mẫu số chung 2 phân số: 23
Vì \(12=12\) nên \(\dfrac{12}{23}=\dfrac{12}{23}\)
Vậy \(\dfrac{48}{92}=\dfrac{36}{69}\)

b)

\(\dfrac{3}{5}+\dfrac{4}{7}+\dfrac{7}{8}=\dfrac{573}{280}\)

Ta có: 
Mẫu số chung 2 phân số: 280
\(\dfrac{3}{1}=\dfrac{3*280}{1*280}=\dfrac{840}{280}\)
Vì \(573< 840\) nên \(\dfrac{573}{280}< \dfrac{840}{280}\)
Vậy \(\dfrac{573}{280}< \dfrac{3}{1}\)

c)
Ta có: 
Mẫu số chung 2 phân số: 10
\(\dfrac{2}{5}=\dfrac{2*2}{5*2}=\dfrac{4}{10}\)
Vì \(1< 4\) nên\(\dfrac{1}{10}< \dfrac{4}{10}\)
Vậy \(\dfrac{1}{10}< \dfrac{2}{5}\)

d)
\(\dfrac{4}{10}=\dfrac{4:2}{10:2}=\dfrac{2}{5}\)
Ta có: 
Mẫu số chung 2 phân số: 5
Vì \(2=2\) nên \(\dfrac{2}{5}=\dfrac{2}{5}\)
Vậy \(\dfrac{4}{10}=\dfrac{2}{5}\)

Hãy quy đồng hộ mình và đánh dấu nha 

Lời giải:

$3\sqrt{7}=\sqrt{3^2.7}=\sqrt{63}$

$4\sqrt{5}=\sqrt{4^2.5}=\sqrt{80}$

Mà $63<80$ nên $3\sqrt{7}< 4\sqrt{5}$

a) Ta có:

\(\dfrac{8}{9}=\dfrac{40}{45}\)

\(\dfrac{7}{5}=\dfrac{63}{45}\)

\(\Rightarrow\dfrac{8}{9}< \dfrac{6}{5}\left(\dfrac{40}{45}< \dfrac{63}{45}\right)\)

b) Ta có:

\(\dfrac{3}{4}=\dfrac{15}{20}\)

\(\dfrac{4}{5}=\dfrac{16}{20}\)

\(\Rightarrow\dfrac{3}{4}< \dfrac{4}{5}\left(\dfrac{15}{20}< \dfrac{16}{20}\right)\)

Câu `5`

`a)` Ta có:

`8/9 < 1 ; 7/5>1`

Vì: `8/9 < 1 < 7/5` nên `8/9 < 7/5`

`b)3/4= 15/20`

`4/5 = 16/20`

Vì: `15/20 < 16/20` nên `3/4<4/5`

hình như là a < b thì phải

Bài làm

-)

\(-\frac{9}{4}=\frac{-9\cdot3}{4\cdot3}=\frac{-27}{12}\)

\(\frac{1}{3}=\frac{1\cdot4}{3\cdot4}=\frac{4}{12}\)

Vì -27 < 4 => -27/12 < 4/12

Do đó: \(-\frac{9}{4}< \frac{1}{3}\)

-)

\(-\frac{8}{3}=\frac{-8\cdot7}{3\cdot7}=\frac{-56}{21}\)

\(\frac{4}{-7}=\frac{4\cdot3}{-7\cdot3}=\frac{12}{-21}=\frac{12\cdot-1}{-21\cdot-1}=\frac{-12}{21}\)

Vì -56 < -12 => -56/21 < -12/21

Do đó: \(-\frac{8}{3}< \frac{4}{-7}\)

-)

\(\frac{9}{-5}=\frac{9\cdot2}{-5\cdot2}=\frac{18}{-10}=\frac{18\cdot-1}{-10\cdot-1}=\frac{-18}{10}\)

\(\frac{7}{-10}=\frac{7\cdot-1}{-10\cdot-1}=\frac{-7}{10}\)

Vì -18 < -7 => -18/10 < -7/10

Do đó: \(\frac{9}{-5}< \frac{7}{-10}\)

a -9/4 < 1/3

b -8/3< 4/-7

c 9/-5 < 7/-10 

ht

9/4>1/3

8/3>4/7]

9/5>7/10

nha

hok tốt nha

ok

ok

nha

a: căn 14<4

=>7+căn 14<4+7=11

b: -căn 5<-2

=>-căn 5+9<-2+9=7

d: \(\sqrt{145}< 13\)
=>-11+căn 145<-11+13=2

e: \(7-4\sqrt{5}+2=9-4\sqrt{5}>0\)

=>7-4căn 5>-2

f: -4căn 5>-9

=>-9-4căn 5>-9-9=-18