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9 tháng 9 2023

\(\dfrac{2}{5}\) x y : \(\dfrac{7}{4}\) = \(\dfrac{7}{8}\)

\(\dfrac{2}{5}\) x y = \(\dfrac{7}{8}\) x \(\dfrac{7}{4}\)

 \(\dfrac{2}{5}\) x y = \(\dfrac{49}{32}\)

         y = \(\dfrac{49}{32}\) : \(\dfrac{2}{5}\)

         y = \(\dfrac{245}{64}\)

9 tháng 9 2023

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

\(\dfrac{12}{5}\): y x \(\dfrac{5}{4}\) = \(\dfrac{13}{5}\)

\(\dfrac{12}{5}\): y        = \(\dfrac{13}{5}\)\(\dfrac{5}{4}\)

 \(\dfrac{12}{5}\): y = \(\dfrac{52}{25}\)

        y = \(\dfrac{12}{5}\)\(\dfrac{52}{25}\)

        y = \(\dfrac{15}{13}\)

 

3 tháng 8 2023

\(a,2\dfrac{2}{5}:y\times1\dfrac{3}{4}=\dfrac{7}{8}\\ \dfrac{12}{5}:y\times\dfrac{7}{4}=\dfrac{7}{8}\\ \dfrac{12}{5}:y=\dfrac{7}{8}:\dfrac{7}{4}\\ \dfrac{12}{5}:y=\dfrac{1}{2}\\ y=\dfrac{12}{5}:\dfrac{1}{2}=\dfrac{24}{5}\\ b,3\dfrac{2}{5}:y:1\dfrac{1}{4}=2\dfrac{3}{5}\\ \dfrac{17}{5}:y:\dfrac{5}{4}=\dfrac{13}{5}\\ y:\dfrac{5}{4}=\dfrac{17}{5}:\dfrac{13}{5}\\ y:\dfrac{5}{4}=\dfrac{17}{13}\\ y=\dfrac{17}{13}\times\dfrac{5}{4}=\dfrac{85}{52}\)

3 tháng 8 2023

\(c,\dfrac{12}{5}-2\dfrac{2}{5}\times y=1\dfrac{1}{4}\\ \dfrac{12}{5}-\dfrac{12}{5}\times y=\dfrac{5}{4}\\ \dfrac{12}{5}\times y=\dfrac{12}{5}-\dfrac{5}{4}\\ \dfrac{12}{5}\times y=\dfrac{23}{20}\\ y=\dfrac{23}{20}:\dfrac{12}{5}\\ y=\dfrac{23}{48}\)

3 tháng 8 2023

\(2\dfrac{2}{5}-y:2\dfrac{3}{4}=1\dfrac{1}{2}\\ \dfrac{12}{5}-y:\dfrac{11}{4}=\dfrac{3}{2}\\ y:\dfrac{11}{4}=\dfrac{12}{5}-\dfrac{3}{2}\\ y:\dfrac{11}{4}=\dfrac{9}{10}\\ y=\dfrac{9}{10}\times\dfrac{11}{4}=\dfrac{99}{40}\\ b,1\dfrac{1}{4}+2\dfrac{1}{5}\times y=2\dfrac{3}{5}\\ \dfrac{5}{4}+\dfrac{11}{5}\times y=\dfrac{13}{5}\\ \dfrac{11}{5}\times y=\dfrac{13}{5}-\dfrac{5}{4}\\ \dfrac{11}{5}\times y=\dfrac{27}{20}\\ y=\dfrac{27}{20}:\dfrac{11}{5}=\dfrac{27}{44}\)

3 tháng 8 2023

\(c,2\dfrac{4}{5}-2\dfrac{1}{4}:y=\dfrac{3}{4}\\ \dfrac{14}{5}-\dfrac{9}{4}:y=\dfrac{3}{4}\\ \dfrac{9}{4}:y=\dfrac{14}{5}-\dfrac{3}{4}\\ \dfrac{9}{4}:y=\dfrac{41}{20}\\ y=\dfrac{9}{4}:\dfrac{41}{20}=\dfrac{45}{41}\\ c2,x:3\dfrac{1}{3}=2\dfrac{2}{5}+\dfrac{7}{10}\\ x:\dfrac{10}{3}=\dfrac{12}{5}+\dfrac{7}{10}\\ x:\dfrac{10}{3}=\dfrac{31}{10}\\ x=\dfrac{31}{10}\times\dfrac{10}{3}=\dfrac{31}{3}\)

19 tháng 2 2023

`3/4 + 5/6 = 9/12 + 10/12 = 19/12`

`1/2 + 7/12 = 6/12 + 7/12 = 13/12`

`2/3 xx 3/4 = 2/4 = 1/2`

`7/4 : 2 = 7/4 xx 1/2 = 7/8`

19 tháng 2 2023

\(a,\dfrac{3}{4}+\dfrac{5}{6}=\dfrac{18}{24}+\dfrac{20}{24}=\dfrac{38}{24}=\dfrac{19}{12}\)

\(b,\dfrac{1}{2}+\dfrac{7}{12}=\dfrac{6}{12}+\dfrac{7}{12}=\dfrac{13}{12}\)

\(c,\dfrac{2}{3}x\dfrac{3}{4}=\dfrac{2}{4}\)

\(d,\dfrac{7}{4}:2=\dfrac{7}{4}x\dfrac{1}{2}=\dfrac{7}{8}\)

25 tháng 8 2023

mình ko chép đề bài nha

a) \(\dfrac{16}{5}\)\(\dfrac{7}{3}\) : y =\(\dfrac{12}{7}\)

    \(\dfrac{48}{35}\): y        = \(\dfrac{12}{7}\)

           y        = \(\dfrac{48}{35}\)\(\dfrac{12}{7}\)

           y        = \(\dfrac{4}{5}\)

 

     

25 tháng 8 2023

a) y = 5/4

b) y = 21

c) y = 41/12

14 tháng 7 2023

2: y \(\times\) \(\dfrac{3}{5}\) = \(\dfrac{9}{10}\)

2:y =  \(\dfrac{9}{10}\) : \(\dfrac{3}{5}\) 

2: y = \(\dfrac{3}{2}\)

    y = 2 : \(\dfrac{3}{2}\)

     y = \(\dfrac{4}{3}\)

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

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

       \(\dfrac{2}{5}\): y = \(\dfrac{1}{4}\)

             y = \(\dfrac{2}{5}\) : \(\dfrac{1}{4}\)

            y = \(\dfrac{8}{5}\)

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

           \(\dfrac{7}{2}\) - y = \(\dfrac{3}{2}\) : \(\dfrac{3}{4}\)

            \(\dfrac{7}{2}\) - y = 2

                   y = \(\dfrac{7}{2}\) - 2

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

   

 

24 tháng 7 2023

1/2-2y=9/20

=>2y=1/2-9/20=1/20

=>y=1/20:2=1/40

b,3/5:4/3:y=2+7/10=9/20:y=27/10

=>y=9/20:27/10=1/6

c,y+y*3/2-y*1/2=1/10

=>y(1+3/2-1/2)=1/10

=>2y=1/10

=>y=1/10:2=1/20

31 tháng 7 2023

` a/` 

 

` 3 1/5 : 2 1/3 : y = 12/7 `

 

` 48/35 : y = 12/7 `

 

` y = 48/35 : 12/7 `

 

` y = 48/35 xx 7/12 `

 

` y = 4/5`

 

Vậy ` y = 4/5` 

 

`b/`

 

` 3 : y xx 3 1/2 = 2/3 xx 3/4 `

 

` 3 : y xx 7/2 =  1/2`

 

` 3 : y = 1/2 : 7/2 `

 

` 3 : y = 1/2 xx 2/7 `

 

` 3 : y = 1/7 `

 

`      y = 3 : 1/7 `

 

`      y = 3 xx 7`

 

`      y = 21 `

 

 Vậy ` y = 21 `

 

`c/` 

 

` 3 2/3 - y + 1 3/4 = 2`

 

` 11/3 - y + 7/4 = 2 `

 

`   11/3 -y  = 2 - 7/4`

 

`    11/3 - y = 1/4 `

 

`        y = 11/3 - 1/4 `

 

`        y = 41/12  `

 

 

Vậy ` y = 41/12`

`a, 2/3 +3/4 = (8+9)/12=17/12.`

`1 1/3+4/5 = 4/3 + 4/5 = (20+12)/15=32/15`.

`=> x=2.`

`b, 5/6-1/4=(20-6)/24=7/12`.

`2 1/3-2/5= 7/3-2/5 = (35-6)/15=29/15`.

`=> x=1`.

25 tháng 9 2023

a) \(\dfrac{2}{3}+\dfrac{3}{4}=\dfrac{8+9}{12}=\dfrac{17}{12}\)

-> 1 1/3 + 4/5 = 4/3 + 4/5 =  20+12/15 = 32/15

vậy x có thể = 14/14 = 1 (x thuộc N)