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6 tháng 3 2017

25/75 = 1/3 ; 17/34 = 1/ 2 ; 121/132 = 11/12

ta quy đồng 1/3 và 1/2 và 11/12

1/3=4/12

1/2=6/12

11/12=11/12

10 tháng 5 2022

refer:

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10 tháng 5 2022

                                =2/3+81/25+8/7       =38/21+81/25 =  2651/525

\(=\left(\dfrac{3}{4}+\dfrac{1}{4}\right)+\left(-\dfrac{17}{25}-\dfrac{8}{25}\right)+\left(\dfrac{13}{37}+\dfrac{24}{37}\right)=1\)

19 tháng 2 2022

1

125/90=25/18

84/91=12/13

75/45=25/15=5/3

10 tháng 5 2022

125/90=25/18

84/91=12/13

75/45=25/15=5/3

6/7=18/21=54/63=104/126

14 tháng 3 2022

\(\dfrac{2}{3}\)

14 tháng 3 2022

\(\dfrac{38}{75}:\dfrac{19}{25}=\dfrac{38}{75}\times\dfrac{25}{19}=\dfrac{2}{3}\)

8 tháng 4 2021

`|-25/10|×0,2+75%:(5/2)^2`

`=25/10×1/5+3/4:25/4`

`=5/10+3/4×4/25`

`=1/2+3/25`

`=25/50+6/50`

`=31/50`

8 tháng 4 2021

Cảm ơn bạn nhiều nhéhehe

 

AH
Akai Haruma
Giáo viên
23 tháng 8 2023

Lời giải:

PT $\Leftrightarrow \frac{x+25}{75}+1+\frac{x+30}{70}+1=\frac{x+35}{65}+1+\frac{x+40}{60}+1$

$\Leftrightarrow \frac{x+100}{75}+\frac{x+100}{70}=\frac{x+100}{65}+\frac{x+100}{60}$
$\Leftrightarrow (x+100)(\frac{1}{75}+\frac{1}{70}-\frac{1}{65}-\frac{1}{60})=0$

Dễ thấy $\frac{1}{75}+\frac{1}{70}-\frac{1}{65}-\frac{1}{60}<0$

$\Rightarrow x+100=0$

$\Leftrightarrow x=-100$ (tm)

 

1) Ta có: \(\left(-\dfrac{2}{3}\right)^2\cdot\dfrac{-9}{8}-25\%\cdot\dfrac{-16}{5}\)

\(=\dfrac{4}{9}\cdot\dfrac{-9}{8}-\dfrac{1}{4}\cdot\dfrac{-16}{5}\)

\(=\dfrac{-1}{2}+\dfrac{4}{5}\)

\(=\dfrac{-5}{10}+\dfrac{8}{10}=\dfrac{3}{10}\)

2) Ta có: \(-1\dfrac{2}{5}\cdot75\%+\dfrac{-7}{5}\cdot25\%\)

\(=\dfrac{-7}{5}\cdot\dfrac{3}{4}+\dfrac{-7}{5}\cdot\dfrac{1}{4}\)

\(=\dfrac{-7}{5}\left(\dfrac{3}{4}+\dfrac{1}{4}\right)=-\dfrac{7}{5}\)

3) Ta có: \(-2\dfrac{3}{7}\cdot\left(-125\%\right)+\dfrac{-17}{7}\cdot25\%\)

\(=\dfrac{-17}{7}\cdot\dfrac{-5}{4}+\dfrac{-17}{7}\cdot\dfrac{1}{4}\)

\(=\dfrac{-17}{7}\cdot\left(\dfrac{-5}{4}+\dfrac{1}{4}\right)\)

\(=\dfrac{17}{7}\)

4) Ta có: \(\left(-2\right)^3\cdot\left(\dfrac{3}{4}\cdot0.25\right):\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)

\(=\left(-8\right)\cdot\left(\dfrac{3}{4}\cdot\dfrac{1}{4}\right):\left(\dfrac{9}{4}-\dfrac{7}{6}\right)\)

\(=\left(-8\right)\cdot\dfrac{3}{16}:\dfrac{54-28}{24}\)

\(=\dfrac{-3}{2}\cdot\dfrac{24}{26}\)

\(=\dfrac{-72}{52}=\dfrac{-18}{13}\)

24 tháng 12 2021

\(K=\left(\dfrac{10}{3}\cdot\dfrac{19}{10}+\dfrac{19}{2}:\dfrac{13}{3}\right)\cdot\dfrac{2}{3}\)

\(=\dfrac{665}{117}\)

24 tháng 12 2021

\(K=\left(\dfrac{10}{3}\cdot\dfrac{19}{10}+\dfrac{19}{2}:\dfrac{13}{3}\right)\cdot\left(\dfrac{62}{75}-\dfrac{12}{25}\right)=\left(\dfrac{19}{3}+\dfrac{57}{26}\right)\cdot\dfrac{2}{3}=\dfrac{665}{78}\cdot\dfrac{2}{3}=\dfrac{665}{117}\)

Sửa đề: \(\dfrac{74-x}{26}+\dfrac{75-x}{25}+\dfrac{76-x}{24}+\dfrac{77-x}{23}+\dfrac{78-x}{22}=-5\)Ta có: \(\dfrac{74-x}{26}+\dfrac{75-x}{25}+\dfrac{76-x}{24}+\dfrac{77-x}{23}+\dfrac{78-x}{22}=-5\)

\(\Leftrightarrow\dfrac{74-x}{26}+1+\dfrac{75-x}{25}+1+\dfrac{76-x}{24}+1+\dfrac{77-x}{23}+1+\dfrac{78-x}{22}+1=0\)

\(\Leftrightarrow\dfrac{100-x}{26}+\dfrac{100-x}{25}+\dfrac{100-x}{24}+\dfrac{100-x}{23}+\dfrac{100-x}{22}=0\)

\(\Leftrightarrow\left(100-x\right)\left(\dfrac{1}{26}+\dfrac{1}{25}+\dfrac{1}{24}+\dfrac{1}{23}+\dfrac{1}{22}\right)=0\)

mà \(\dfrac{1}{26}+\dfrac{1}{25}+\dfrac{1}{24}+\dfrac{1}{23}+\dfrac{1}{22}>0\)

nên 100-x=0

hay x=100

Vậy: S={100}

9 tháng 2 2021

Ta có : \(\dfrac{74-x}{26}+\dfrac{75-x}{25}+\dfrac{76-x}{24}+\dfrac{77-x}{23}+\dfrac{78-x}{22}=-5\)

\(\Leftrightarrow\dfrac{74-x}{26}+\dfrac{75-x}{25}+\dfrac{76-x}{24}+\dfrac{77-x}{23}+\dfrac{78-x}{22}+5=0\)

\(\Leftrightarrow\dfrac{74-x}{26}+1+\dfrac{75-x}{25}+1+\dfrac{76-x}{24}+1+\dfrac{77-x}{23}+1+\dfrac{78-x}{22}+1=0\)

\(\Leftrightarrow\dfrac{100-x}{26}+\dfrac{100-x}{25}+\dfrac{100-x}{24}+\dfrac{100-x}{23}+\dfrac{100-x}{22}=0\)

\(\Leftrightarrow\left(100-x\right)\left(\dfrac{1}{26}+\dfrac{1}{25}+\dfrac{1}{24}+\dfrac{1}{23}+\dfrac{1}{22}\right)=0\)

Thấy : \(\dfrac{1}{26}+\dfrac{1}{25}+\dfrac{1}{24}+\dfrac{1}{23}+\dfrac{1}{22}\ne0\)

\(\Rightarrow100-x=0\)

\(\Leftrightarrow x=100\)

Vậy ...

 

 

 

 

 

 

 

 

 

 

 

 

 

12 tháng 5 2021

giúp mik nhoa mik đag cần gấp hihi

12 tháng 5 2021

a) \(x=\dfrac{-3.\left(-5\right)}{15}=1\)

b) \(x=\dfrac{5.1173}{3}=1955\)