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DD
20 tháng 1 2021

\(\frac{3}{4}+\frac{1}{3}\times a=\frac{7}{6}\)

\(\Leftrightarrow\frac{1}{3}\times a=\frac{7}{6}-\frac{3}{4}=\frac{5}{12}\)

\(\Leftrightarrow a=\frac{5}{12}\div\frac{1}{3}=\frac{5}{4}\).

\(a-\frac{1}{4}=\frac{5}{4}-\frac{1}{4}=1\)

19 tháng 8 2023

Bài 1:

câu a: 4\(\dfrac{4}{9}\) : 2\(\dfrac{2}{3}\) + 3\(\dfrac{1}{6}\)

        = \(\dfrac{40}{9}\) : \(\dfrac{8}{3}\) + \(\dfrac{19}{6}\)

        = \(\dfrac{5}{3}\) + \(\dfrac{19}{6}\)

         = \(\dfrac{10}{6}\) + \(\dfrac{19}{6}\)

          = \(\dfrac{29}{6}\)

b, (15,25 + 3,75) \(\times\) 4 + ( 20,71 + 5,29)\(\times\) 5

     = 19 \(\times\) 4 + 26 \(\times\) 5

     = 76 + 130

     = 206

19 tháng 8 2023

c, \(\dfrac{4}{5}\) \(\times\) \(\dfrac{1}{2}\) + \(\dfrac{4}{5}\) \(\times\) \(\dfrac{1}{3}\) - \(\dfrac{4}{5}\) \(\times\) \(\dfrac{1}{4}\)

\(\dfrac{2}{5}\)    + \(\dfrac{4}{15}\) - \(\dfrac{1}{5}\)

\(\dfrac{6}{15}\) + \(\dfrac{4}{15}\) - \(\dfrac{3}{15}\)

\(\dfrac{7}{15}\) 

d, 1\(\dfrac{5}{7}\) + 7\(\dfrac{3}{6}\) + 2\(\dfrac{2}{7}\) - 4\(\dfrac{3}{6}\)

= (1 + 2 + \(\dfrac{5}{7}\) + \(\dfrac{2}{7}\)) + ( 7 + \(\dfrac{3}{6}\) - 4 - \(\dfrac{3}{6}\))

=  3 + 1 + 3 

= 7

15 tháng 9 2021

\(\left(x+\frac{3}{4}\right)\times\frac{5}{7}=\frac{10}{9}\)

\(\left(x+\frac{3}{4}\right)=\frac{10}{9}\div\frac{5}{7}\)

\(x+\frac{3}{4}=\frac{14}{9}\)

\(x=\frac{14}{9}-\frac{3}{4}\)

\(x=\frac{29}{36}\)

15 tháng 9 2021

\(x+\frac{3}{4}\)\(=\frac{10}{9}\)\(:\frac{5}{7}\)\(=\frac{10}{9}\)\(x\frac{7}{5}\)\(=\frac{14}{9}\)

\(x=\frac{14}{9}\)\(-\frac{3}{4}\)

\(x=\frac{56}{36}\)\(-\frac{27}{36}\)

\(x=\frac{29}{36}\)

21 tháng 9 2023

a, 7\(\dfrac{3}{5}\) : \(x\) = 5\(\dfrac{4}{15}\) - 1\(\dfrac{1}{6}\)

     \(\dfrac{38}{5}\) : \(x\) = \(\dfrac{79}{15}\) - \(\dfrac{7}{6}\)

              \(x\) = \(\dfrac{41}{10}\)

             \(x\) = \(\dfrac{38}{5}\) : \(\dfrac{41}{10}\)

              \(x\) = \(\dfrac{76}{41}\)

           

       

21 tháng 9 2023

b, \(x\) \(\times\) 2\(\dfrac{2}{3}\) = 3\(\dfrac{4}{8}\) + 6\(\dfrac{5}{12}\)

    \(x\) \(\times\) \(\dfrac{8}{3}\)  = \(\dfrac{7}{2}\) + \(\dfrac{77}{12}\)

     \(x\) \(\times\) \(\dfrac{8}{3}\) = \(\dfrac{119}{12}\)

     \(x\)          = \(\dfrac{119}{12}\)

     \(x\)          = \(\dfrac{119}{12}\)\(\dfrac{8}{3}\)

     \(x\)           = \(\dfrac{119}{32}\)

14 tháng 6 2017

a)x : 3 - 7 * 2 = 1,56

  x : 3 - 14 = 1,56

  x : 3 = 1,56 + 14

  x : 3 = 15,56

  x = 15,56 * 3

  x = 46,68

b)nếu dấu chấm trên đề là dấu phẩy thì:

  x : 6,4 = 1,248

  x = 1,248 * 6,4

  x = 7,9872

c)(x + 1) + (x + 2) + (x + 3) + (x + 4) + (x + 5) = 40

  x + 1 + x + 2 + x + 3 + x + 4 + x + 5 = 40

  (x + x + x + x + x) + (1 + 2 + 3 + 4 + 5) = 40

  5 * x + 15 = 40

  5 * x = 40 - 15

  5 * x = 25

  x = 25 : 5

  x = 5

14 tháng 6 2017

A) X:3 - 7 * 2 = 1,56

   X:3-14=1,56

   X:3=1,56+14

   X:3=5,56

  X= 5,56* 3 =16,68

B) X : 6 . 4 = 1 ,248

 X = 1,248 :4 *6

X=1,872

C)  ĐỀ DÀI LÀM LUN

 = 5X + (1+2+3+4+5) =40

5X+15 =40

5X= 40-15=25

X= 25:5=5

3 tháng 10 2020

X x 3 1/3= 3 1/3 : 4 1/4

X x 10/3=10/3:17/4

X x 10/3= 10/3:17/4

X x 10/3= 40/51

X           = 40/51:10/3

X           = 120/510

X           = 12/51

X           = 4/17

26 tháng 8 2023

\(A=\dfrac{2}{1x3}+\dfrac{2}{3x5}+\dfrac{2}{5x7}+...+\dfrac{2}{21x23}\)

\(A=2x\left(\dfrac{1}{1x3}+\dfrac{1}{3x5}+\dfrac{1}{5x7}+...+\dfrac{1}{21x23}\right)\)

\(A=2x\dfrac{1}{2}x\left(1-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+...+\dfrac{1}{21}-\dfrac{1}{23}\right)\)

\(A=1-\dfrac{1}{23}\)

\(A=\dfrac{22}{23}\)

26 tháng 8 2023

\(B=\dfrac{1}{6}+\dfrac{1}{12}+\dfrac{1}{20}+\dfrac{1}{30}+\dfrac{1}{42}+\dfrac{1}{56}+\dfrac{1}{72}+\dfrac{1}{90}\)

\(B=\dfrac{1}{2x3}+\dfrac{1}{3x4}+\dfrac{1}{4x5}+\dfrac{1}{5x6}+\dfrac{1}{6x7}+\dfrac{1}{7x8}+\dfrac{1}{8x9}+\dfrac{1}{9x10}\)

\(B=\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{10}\)

\(B=\dfrac{1}{2}-\dfrac{1}{10}\)

\(B=\dfrac{5}{10}-\dfrac{1}{10}\)

\(B=\dfrac{4}{10}\)

\(B=\dfrac{2}{5}\)

22 tháng 9 2023

\(\dfrac{3}{5}\times\dfrac{4}{7}\times1\dfrac{1}{2}\)

\(=\dfrac{3}{5}\times\dfrac{4}{7}\times\dfrac{3}{2}\)

\(=\dfrac{3\times4\times3}{5\times7\times2}\)

\(=\dfrac{3\times2\times3}{5\times7}\)

\(=\dfrac{18}{35}\)

17 tháng 8 2020

5/4-yx5/6=-1/12

5/4-y      = -1/12:5/6

5/4-y      = -1/10

y            = 5/4-(-1/10)

y            = 27/20

17 tháng 8 2020

\(\frac{5}{4}-y.\frac{5}{6}=\frac{1}{4}-\frac{1}{3}\)

\(\Rightarrow\frac{5}{4}-y.\frac{5}{6}=-\frac{1}{12}\)

\(\Rightarrow y.\frac{5}{6}=\frac{5}{4}-\left(-\frac{1}{12}\right)\)

\(\Rightarrow y.\frac{5}{6}=\frac{5}{4}+\frac{1}{12}\)

\(\Rightarrow y.\frac{5}{6}=\frac{4}{3}\)

\(\Rightarrow y=\frac{4}{3}:\frac{5}{6}\)

\(\Rightarrow y=\frac{8}{5}\)

Vậy  \(y=\frac{8}{5}.\)

3 tháng 1

\(\left(\dfrac{1}{4}+35\%+0,65+75\%\right)\times\left(1\dfrac{6}{9}+4\dfrac{8}{24}\right)\)

\(=\left(0,25+0,35+0,65+0,75\right)\times\left(1+\dfrac{2}{3}+4+\dfrac{1}{3}\right)\)

\(=2\times6\)

\(=12\)

\(\left(\dfrac{1}{4}+35\%+0,65+75\%\right)\times\left(1\dfrac{6}{9}+4\dfrac{8}{24}\right)\)

\(=\left(\dfrac{1}{4}+\dfrac{7}{20}+\dfrac{65}{100}+\dfrac{3}{4}\right)\times\left(\dfrac{15}{9}+\dfrac{13}{3}\right)\)

\(=\left(\dfrac{5}{20}+\dfrac{7}{20}+\dfrac{13}{20}+\dfrac{15}{20}\right)\times6\)

\(=\left[\left(\dfrac{15}{20}+\dfrac{5}{20}\right)+\left(\dfrac{7}{20}+\dfrac{13}{20}\right)\right]\times6\)

\(=2\times6\)

\(=12\)