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\(\frac{3-x}{5-x}=\frac{9}{25}\)

\(\Rightarrow\left(3-x\right)\cdot25=\left(5-x\right)\cdot9\)

\(75-25x=45-9x\)

\(75-25x+9x=45\)

\(14x=30\)

\(x=30\div14\)

\(x=\frac{15}{7}\)

6 tháng 4 2017

ủng hộ cho mk nha mọi người

1 tháng 8 2020

Ta có \(\frac{9}{25}x+\frac{3}{5}.\frac{9}{25}x+\frac{3}{5}.18+\frac{9}{25}x+18=x\)

=> \(\frac{9}{25}x\left(1+\frac{3}{5}+1\right)+18\left(\frac{3}{5}+1\right)=x\)

=> \(\frac{117}{125}x+28,8=x\)

=> \(x-\frac{117}{125}x=28,8\)

=> \(\frac{8}{125}x=28,8\)

=> x = 450

Vậy x = 450

1 tháng 8 2020

\(\frac{9}{25}x+\frac{3}{5}.\frac{9}{25}x+\frac{3}{5}.18+\frac{9}{25}x+18=x\)

\(x\left(\frac{9}{25}+\frac{9}{25}+\frac{9}{25}\right).\frac{3}{5}+\frac{3}{5}.18+18=x\)

\(x.\frac{3}{5}\left(\frac{27}{25}+18\right)+18=x\)

\(x.\frac{3}{5}\left(\frac{27}{25}+\frac{450}{25}\right)+18=x\)

\(x.\frac{3}{5}.\frac{477}{25}+18=x\)

\(x.\frac{1431}{125}+\frac{2250}{125}=x\)

\(x.\frac{3681}{125}=x\)

vậy chac tui làm sai rồi

16 tháng 8 2015

\(\frac{3-x}{5}=\frac{9}{25}\)

\(\Rightarrow\left(3-x\right).25=9.5\)

\(75-25x=45\)

\(25x=75-45\)

\(25x=30\)

\(x=\frac{30}{25}\)

\(x=\frac{6}{5}\)

16 tháng 8 2015

1,2                              

\(\left(2x+\frac{3}{5}\right)^2-\frac{9}{25}=0\)

\(\Leftrightarrow\left(2x+\frac{3}{5}\right)^2=\frac{9}{25}\)

\(\Leftrightarrow\left(2x+\frac{3}{5}\right)^2=\left(\frac{3}{5}\right)^2\)

\(\Leftrightarrow\orbr{\begin{cases}2x+\frac{3}{5}=\frac{3}{5}\\2x+\frac{3}{5}=-\frac{3}{5}\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}2x=0\\2x=-\frac{6}{5}\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x=0\\x=-\frac{3}{5}\end{cases}}\)

_Tần vũ_

\(3\left(3x-\frac{1}{2}\right)^3+\frac{1}{9}=0\)

\(\Leftrightarrow3\left(3x-\frac{1}{2}\right)^3=-\frac{1}{9}\)

\(\Leftrightarrow\left(3x-\frac{1}{2}\right)^3=-\frac{1}{27}\)

\(\Leftrightarrow\left(3x-\frac{1}{2}\right)^3=\left(-\frac{1}{3}\right)^3\)

\(\Leftrightarrow3x-\frac{1}{2}=\frac{-1}{3}\)

\(\Leftrightarrow3x=\frac{1}{6}\)

\(\Leftrightarrow x=\frac{1}{18}\)

_Tần Vũ_

23 tháng 7 2018

29-x/21 + 27-x/23 + 25-x/25 + 23-x/27 + 21-x/29 = -5

1 + 29-x/21 + 1 + 27-x/23 + 1 + 25-x/25 + 1 + 23-x/27 + 1 + 21-x/29 = 0 

50-x/21 + 50-x/23 + 50-x/25 + 50-x/27 + 50-x/29 = 0

(50-x) (1/21 + 1/23 + 1/25 + 1/27 + 1/29) = 0

Vì: 1/21 + 1/23 + 1/25 + 1/27 + 1/2 > 0

=> 50 - x = 0

             x = 50

Vậy x = 50

21 tháng 7 2018

\(\frac{-1}{3}+\frac{0,2-0,3+\frac{5}{11}}{-0,3+\frac{9}{16}-\frac{15}{12}}\)

\(=\frac{-1}{3}+\frac{\frac{2}{10}-\frac{3}{10}+\frac{5}{11}}{\frac{-3}{10}+\frac{9}{16}-\frac{15}{12}}\)

\(=\frac{-1}{3}+\frac{\frac{39}{110}}{\frac{-79}{80}}\)

\(=\frac{-1}{3}-\frac{312}{869}\)

\(=\frac{-1805}{2607}\)

9 tháng 3 2018

a) \(x=\frac{7}{25}+\frac{-1}{5}=\frac{7}{25}+\frac{-5}{25}=\frac{2}{25}\)

b) \(x=\frac{5}{11}+\frac{4}{-9}=\frac{45}{99}+\frac{-44}{99}=\frac{1}{99}\)

c) \(\frac{5}{9}+\frac{x}{-1}=\frac{-1}{3}\)

\(\Rightarrow\frac{x}{-1}=\frac{-1}{3}-\frac{5}{9}\)

\(\Rightarrow\frac{x}{-1}=\frac{-8}{9}\)

\(\Rightarrow x=\frac{\left(-8\right).\left(-1\right)}{9}=\frac{8}{9}\)

11 tháng 9 2020

\(a.\left(x-1\right)^2=\frac{9}{25}\)

\(\left(x-1\right)^2=\left(\frac{3}{5}\right)^2\)

\(x-1=\frac{3}{5}\)

\(x=\frac{3}{5}+1\)

\(x=\frac{8}{5}\)

\(b.\frac{1}{2}-\frac{1}{3}.x=\frac{4}{5}\)

\(\frac{1}{3}.x=\frac{1}{2}-\frac{4}{5}\)

\(\frac{1}{3}.x=\frac{-3}{10}\)

\(x=\frac{-3}{10}:\frac{1}{3}\)

\(x=\frac{-3}{10}.\frac{3}{1}\)

\(x=\frac{-9}{10}\)

a) \(\left(x-1\right)^2=\frac{9}{25}\)

\(\left(x-1\right)^2=\left(\frac{3}{5}\right)^2\)

\(TH1:x-1=\frac{3}{5}\Rightarrow x=\frac{8}{5}\)

\(TH2:x-1=-\frac{3}{5}\Rightarrow-\frac{3}{5}+1=\frac{2}{5}\)

\(\Rightarrow x\in\left\{\frac{8}{5};\frac{2}{5}\right\}\)

b) \(\frac{1}{2}-\frac{1}{3}x=\frac{4}{5}\)

\(\frac{1}{3}x=\frac{1}{2}-\frac{4}{5}=-\frac{3}{10}\)

\(x=-\frac{3}{10}:\frac{1}{3}\)

\(x=-\frac{9}{10}\)