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

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24 tháng 10 2019

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

\(5\cdot\left(x-2\right)=3\cdot4\)

\(5x-10=12\)

\(5x=22\)

\(x=\frac{22}{5}\)

24 tháng 10 2019

học giỏi ghê

11 tháng 9 2017

A = \(\frac{5}{4}.\left(5-\frac{4}{3}\right).\frac{1}{11}\)

A = \(\frac{5}{44}\left(5-\frac{4}{3}\right)\)

A = \(\frac{25}{44}-\frac{5}{33}\)

A = \(\frac{25.3}{4.11.3}-\frac{5.4}{3.11.4}\)

A = \(\frac{75}{132}-\frac{20}{132}\)

A = \(\frac{55}{132}\)

B = \(\frac{3}{4}:\left(-12\right).\left(-\frac{2}{3}\right)\)

B = \(\frac{-1}{16}.\left(-\frac{2}{3}\right)\)

B = \(\frac{1}{24}\)

C = \(\frac{5}{4}:\left(-15\right).\left(-\frac{2}{5}\right)\)

C = \(\frac{-1}{12}.\left(-\frac{2}{5}\right)\)

C = \(\frac{1}{30}\)

D = \(\left(-3\right).\left(\frac{2}{3}-\frac{5}{4}\right):\left(-7\right)\)

D = \(\frac{3}{7}.\left(\frac{8}{12}-\frac{15}{12}\right)\)

D = \(\frac{3}{7}.\left(-\frac{7}{12}\right)\)

D = \(\frac{-3}{12}\)

D = \(\frac{-1}{4}\)

2: =>2x-1/4=5/6-1/2x

=>5/2x=5/6+1/4=13/12

=>x=13/30

3: =>3x-5/6=2/3-1/2x

=>3,5x=2/3+5/6=4/6+5/6=9/6=3,2

hay x=32/35

18 tháng 7 2018

a,x-2/5=5/7

x=5/7+2/5

x=39/35

b,-2/5.x=4/15

x=4/15:-2/5

x=-2/3

18 tháng 7 2018

a) \(x-\frac{2}{5}=\frac{5}{7}\)

\(x=\frac{2}{5}+\frac{5}{7}\)

\(x=\frac{14}{35}+\frac{25}{35}=\frac{39}{35}\)

b)

\(\frac{-2}{5}x=\frac{4}{15}\)

\(x=\frac{4}{15}:-\frac{2}{5}\)

\(x=\frac{4}{15}\cdot-\frac{5}{2}=-\frac{2}{3}\)

c) \(2x\left(x-\frac{1}{7}\right)=2x^2-\frac{2x}{7}\)

d) \(\frac{1}{2}+\frac{3}{4}x=\frac{1}{4}\)

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

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

\(x=-\frac{1}{4}\cdot\frac{4}{3}=-\frac{1}{3}\)

f) \(\frac{11}{12}-\left(\frac{2}{5}+x\right)=\frac{2}{5}\)

\(\frac{2}{5}+x=\frac{11}{12}-\frac{2}{5}=\frac{31}{60}\)

\(x=\frac{31}{60}-\frac{2}{5}=\frac{7}{60}\)

a: =>x-8/5=1/20-1/10=-1/20

=>x=-0,05+1,6=1,55

b: =>x-3/2=4/3 hoặc x-3/2=-4/3

=>x=17/6 hoặc x=1/6

c: =>\(\left|x-\dfrac{1}{3}\right|=\dfrac{5}{2}-\dfrac{1}{4}+\dfrac{2}{3}=\dfrac{35}{12}\)

=>x-1/3=35/12 hoặc x-1/3=-35/12

=>x=39/12=13/4 hoặc x=-31/12

d: =>|x-5/8|=3/4

=>x-5/8=3/4 hoặc x-5/8=-3/4

=>x=11/8 hoặc x=-1/8

14 tháng 10 2020

a) \(\left|2x+\frac{3}{4}\right|=\frac{1}{2}\)

     \(\orbr{\begin{cases}2x+\frac{3}{4}=\frac{1}{2}\\2x+\frac{3}{4}=\frac{-1}{2}\end{cases}}\) =>   \(\orbr{\begin{cases}2x=\frac{1}{2}-\frac{3}{4}\\2x=\frac{-1}{2}-\frac{3}{4}\end{cases}}\)  =>   \(\orbr{\begin{cases}2x=\frac{-1}{4}\\2x=\frac{-5}{4}\end{cases}}\) =>   \(\orbr{\begin{cases}x=\frac{-1}{8}\\x=\frac{-5}{8}\end{cases}}\)

Vậy \(x=\left\{\frac{-1}{8},\frac{-5}{8}\right\}\)

b) \(\frac{3x}{2,7}=\frac{\frac{1}{4}}{2\frac{1}{4}}\)\(\frac{3x}{2,7}=\frac{\frac{1}{4}}{\frac{9}{4}}\)

=> \(3x.\frac{9}{4}=2,7.\frac{1}{4}\)=>  \(\frac{27x}{4}=\frac{27}{40}\)

\(27x.40=27.4\)

\(1080.x=108\)

             \(x=\frac{1}{10}\)

Vậy \(x=\frac{1}{10}\)

c) \(\left|x-1\right|+4=6\)

\(\left|x-1\right|=6-4\)

\(\left|x-1\right|=2\)

\(\orbr{\begin{cases}x-1=2\\x-1=-2\end{cases}}\)=>  \(\orbr{\begin{cases}x=3\\x=-1\end{cases}}\)

Vậy \(x=\left[3,-1\right]\)

d) \(\frac{x}{3}=\frac{y}{5}=>\frac{y}{5}=\frac{x}{3}=>\frac{y-x}{5-3}=\frac{24}{2}=12\)

e) \(\left(x^2-3\right)^2=16\)

\(\left(x^2-3\right)^2=4^2\)\(=>x^2-3=4\)

\(x^2=7=>x=\sqrt{7}\)

Vậy \(x=\sqrt{7}\)

f) \(\frac{3}{4}+\frac{2}{5}x=\frac{29}{60}\)

               \(\frac{2}{5}x=\frac{29}{60}-\frac{3}{4}\) 

               \(\frac{2}{5}x=-\frac{4}{15}\)

          \(x=-\frac{4}{15}:\frac{2}{5}=-\frac{4}{15}.\frac{5}{2}=-\frac{2}{3}\)

Vậy \(x=-\frac{2}{3}\)

g) \(\left(-\frac{1}{3}\right)^3.x=\frac{1}{81}\)

\(\left(-\frac{1}{27}\right).x=\frac{1}{81}\)

\(x=\left(-\frac{1}{27}\right):\frac{1}{81}=\left(-\frac{1}{27}\right).81=-3\)

Vậy \(x=-3\)

k)\(\frac{3}{4}-\frac{2}{5}x=\frac{29}{60}\)

\(\frac{2}{5}x=\frac{3}{4}-\frac{29}{60}\)

\(\frac{2}{5}x=\frac{4}{15}\)

      \(x=\frac{2}{5}-\frac{4}{15}=>x=\frac{2}{15}\)

Vậy \(x=\frac{2}{15}\)

I) \(\frac{3}{5}x-\frac{1}{2}=-\frac{1}{7}\)

\(\frac{3}{5}x=-\frac{1}{7}+\frac{1}{2}\)

\(\frac{3}{5}x=\frac{5}{14}\)

\(x=\frac{5}{14}:\frac{3}{5}=\frac{5}{14}.\frac{5}{3}=\frac{25}{42}\)

Vậy \(x=\frac{25}{42}\)