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23 tháng 7 2016

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

\(\Rightarrow\frac{1}{3}x:\frac{2}{3}=\frac{35}{8}\)

\(\Rightarrow\frac{1}{3}x=\frac{35}{12}\)

\(\Rightarrow x=\frac{35}{4}\)

a) \(\left(\frac{1}{3}\cdot x\right):\frac{2}{3}=1\frac{3}{4}:\frac{2}{5}\)

\(=\left(\frac{1}{3}\cdot x\right):\frac{2}{3}=\frac{35}{8}\)

\(\Rightarrow\frac{1}{3}\cdot x=\frac{35}{8}\cdot\frac{2}{3}\)

\(\Rightarrow x=\frac{35}{12}:\frac{1}{3}=\frac{35}{4}\)

b) \(4,5:0,3=2,5:\left(0,1\cdot x\right)\)

\(=15=2,5:\left(0,1\cdot x\right)\)

\(\Rightarrow0,1\cdot x=2,25:15\)

\(\Rightarrow x=\frac{3}{20}:0,1=\frac{3}{2}=1,5\)

c) \(8:\left(\frac{1}{4}\cdot x\right)=2:0,02\)

\(8:\left(\frac{1}{4}\cdot x\right)=100\)

\(\Rightarrow\frac{1}{4}\cdot x=8:100\)

\(\Rightarrow x=\frac{2}{25}:\frac{1}{4}=\frac{8}{25}=0,32\)

d) \(3:2\frac{1}{4}=\frac{3}{4}:\left(6\cdot x\right)\)

\(=\frac{4}{3}=\frac{3}{4}:\left(6:x\right)\)

\(\Rightarrow6\cdot x=\frac{3}{4}:\frac{4}{3}\)

\(\Rightarrow x=\frac{9}{16}:6=\frac{3}{32}=0,09375\)

14 tháng 7 2016

làm 1 bài mẫu nha

a) \(\left(\frac{1}{3}.x\right):\frac{2}{3}=\frac{25}{6}\)

\(\Rightarrow\frac{1}{3}x=\frac{25}{9}\)

\(\Rightarrow x=\frac{25}{9}:\frac{1}{3}\)

\(\Rightarrow x=\frac{25}{3}\)

các bài sau dễ lắm

a) \(\left(\frac{1}{3}x\right):\frac{2}{3}=1\frac{2}{3}:\frac{2}{5}\)

\(\Rightarrow\frac{1}{3}x:\frac{2}{3}=\frac{25}{6}\)

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

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

\(\Rightarrow x=5\)

3 tháng 10 2017

a)\(\left(\frac{1}{3}.x\right):\frac{2}{3}=\frac{7}{4}.\frac{5}{2}\)

\(\left(\frac{1}{3}.x\right):\frac{2}{3}=\frac{35}{8}\)

\(\frac{1}{3}.x=\frac{35}{8}.\frac{2}{3}\)

\(\frac{1}{3}.x=\frac{35}{12}\)

\(x=\frac{35}{12}:\frac{1}{3}\)

\(x=\frac{35}{12}.\frac{3}{1}\)

\(x=\frac{35}{4}\)

b)\(\frac{4,5}{0,3}=\frac{2,25}{0,1.x}\)

\(4,5.\left(0,1.x\right)=2,25.0,3\)

\(4,5.\left(0,1.x\right)=0,675\)

\(0,1.x=0,675:4,5\)

\(0,1.x=0,15\)

\(x=0,15:0,1\)

\(x=1.5\)

c)\(\frac{8}{\frac{1}{4}.x}=\frac{2}{0,02}\)

\(\left(\frac{1}{4}.x\right).2=8.0,02\)

\(\left(\frac{1}{4}.x\right).2=0,16\)

\(\frac{1}{4}.x=0,16:2\)

\(\frac{1}{4}.x=0,08\)

\(x=0,08:\frac{1}{4}\)

\(x=0,32\)

d)\(\frac{3}{\frac{9}{4}}=\frac{\frac{3}{4}}{6.x}\)

\(3.\left(6.x\right)=\frac{3}{4}.\frac{9}{4}\)

\(3.\left(6.x\right)=\frac{27}{16}\)

\(6.x=\frac{27}{16}:3\)

\(6.x=\frac{9}{16}\)

\(x=\frac{9}{16}:6\)

\(x=\frac{3}{32}\)

HỌC TỐT ^^

16 tháng 7 2016

a)4,5:0,3=2,25:(0,1.x)

   2,25:(0,1.x)=15

   0,1.x=0,15

   x=0,15:0,1

   x=1,5

Vậy x=1,5

b)8:\(\left(\frac{1}{4}.x\right)\)=2:0,02

   8:\(\left(\frac{1}{4}.x\right)\)=100

       \(\left(\frac{1}{4}.x\right)\)=\(\frac{8}{100}\)

        x=\(\frac{8}{100}\):\(\frac{1}{4}\)

         x=\(\frac{8}{25}\)

Vậy x=\(\frac{8}{25}\)

c)\(3:2\frac{1}{4}=\frac{3}{4}:\left(6.x\right)\)

   \(\frac{3}{4}:\left(6.x\right)=\frac{4}{3}\)

    6.x=\(\frac{3}{4}:\frac{4}{3}\)

    6.x=\(\frac{9}{16}\)

    x=\(\frac{9}{16}\):6

    x=\(\frac{3}{32}\)

Vậy x=\(\frac{3}{32}\)

16 tháng 7 2016

a.

\(4,5\div0,3=2,25\div\left(0,1\times x\right)\)

\(2,25\div\left(0,1\times x\right)=15\)

\(0,1\times x=\frac{2,25}{15}\)

\(0,1\times x=0,15\)

\(x=\frac{0,15}{0,1}\)

\(x=1,5\)

b.

\(8\div\left(\frac{1}{4}\times x\right)=2\div0,02\)

\(8\div\left(\frac{1}{4}\times x\right)=100\)

\(\frac{1}{4}\times x=\frac{8}{100}\)

\(\frac{1}{4}\times x=\frac{2}{25}\)

\(x=\frac{2}{25}\div\frac{1}{4}\)

\(x=\frac{2}{25}\times4\)

\(x=\frac{8}{25}\)

c.

\(3\div2^1_4=\frac{3}{4}\div\left(6\times x\right)\)

\(\frac{3}{4}\div\left(6\times x\right)=3\div2,25\)

\(\frac{3}{4}\div\left(6\times x\right)=\frac{4}{3}\)

\(6\times x=\frac{3}{4}\div\frac{4}{3}\)

\(6\times x=\frac{3}{4}\times\frac{3}{4}\)

\(6\times x=\frac{9}{16}\)

\(x=\frac{9}{16}\div6\)

\(x=\frac{9}{16}\times\frac{1}{6}\)

\(x=\frac{3}{32}\)

21 tháng 1 2017

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

\(\Rightarrow3.\frac{1}{4}+\frac{1}{4}.x=\frac{1}{2}.\left(x+1\right)\)

\(\Rightarrow\frac{1}{4}.\left(x+3\right)=\frac{1}{2}.\left(x+1\right)\)

\(\Rightarrow\frac{x+1}{x+3}=\frac{1}{4}:\frac{1}{2}=\frac{1}{2}\)\(\Rightarrow\left(x+1\right).2=x+3\Rightarrow2x+2=x+3\)

\(\Rightarrow2x-x=3-2\Rightarrow x=1\)

vay x=1

4 tháng 9 2015

a. => (1/3.x):2/3=7/4:2/5

=> 1/3.x=(7/4.2/3):2/5

=> 1/3.x=7/6.5/2

=> 1/3.x=35/12

=> x=35/12:1/3

=> x=35/12.3

=> x=35/4

b. => 4,5.(0,1.x)=0,3.2,25

=> 4,5.(0,1.x)=0,675

=> 0,1.x=0,675:4,5

=> 0,1.x=0,15

=> x=0,15:0,1

=> x=1,5

c. => 2.(1/4.x)=8.0,02

=> 1/2.x=0,16

=> x=0,16:1/2

=> x=0,16.2

=> x=0,32

d. => 3:9/4=3/4:(6.x)

=> 3.(6.x)=9/4.3/4

=> 18.x=27/16

=> x=27/16:18

=> x=27/16.1/18

=> x=3/32

17 tháng 7 2017

a) ( 1/3 . x ) : 2/3 = 7/4 : 2/5

       1/3 . x  : 2/3  = 35/8

        1/3 . x          = 35/8 . 2/3

         1/3 . x          = 35/12

                 x          = 35/12 : 1/3

                 x          = 35/4

   

26 tháng 10 2016

a ) \(\left(\frac{2}{5}-x\right):1\frac{1}{3}+\frac{1}{2}=-4\)

     \(\left(\frac{2}{5}-x\right):\frac{4}{3}+\frac{1}{2}=-4\)

     \(\left(\frac{2}{5}-x\right):\frac{4}{3}=-4-\frac{1}{2}\)

     \(\left(\frac{2}{5}-x\right):\frac{4}{3}=-\frac{9}{2}\)

        \(\frac{2}{5}-x=-\frac{9}{2}.\frac{4}{3}\)

        \(\frac{2}{5}-x=-3\)

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

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

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

                   \(x=-\frac{12}{5}\)

Vay \(x=-\frac{12}{5}\) 

    

  

26 tháng 10 2016

b ) \(\left(-3+\frac{3}{x}-\frac{1}{3}\right):\left(1+\frac{2}{5}+\frac{2}{3}\right)=-\frac{5}{4}\)

     \(\left(-3+\frac{3}{x}-\frac{1}{3}\right):\left(\frac{15}{15}+\frac{6}{15}+\frac{10}{15}\right)=-\frac{5}{4}\)

     \(\left(-3+\frac{3}{x}-\frac{1}{3}\right):\left(\frac{15+6+10}{15}\right)=-\frac{5}{4}\)

     \(\left(-3+\frac{3}{x}-\frac{1}{3}\right):\frac{31}{15}=-\frac{5}{4}\)

     \(\left(-3+\frac{3}{x}-\frac{1}{3}\right)=-\frac{5}{4}.\frac{31}{15}\)

     \(\left(-3+\frac{3}{x}-\frac{1}{3}\right)=-\frac{1}{4}.\frac{31}{3}\)

        \(-3+\frac{3}{x}-\frac{1}{3}=-\frac{31}{12}\)

        \(-3+\frac{3}{x}=-\frac{31}{12}+\frac{1}{2}\)

        \(-3+\frac{3}{x}=-\frac{31}{12}+\frac{6}{12}\)

        \(-3+\frac{3}{x}=\frac{-25}{12}\)

                     \(\frac{3}{x}=\frac{-25}{12}+3\)

                      \(\frac{3}{x}=\frac{-25}{12}+\frac{36}{12}\)

                      \(\frac{3}{x}=\frac{5}{6}\)

                      \(\frac{18}{6x}=\frac{5x}{6x}\)

Đèn dây , bạn tự làm tiếp nhé , de rồi chứ