NI

x ; 1/5=7
x x 2/3=9
1--3/7+x=2--1/5 hỗn số 
4--1/3-x=2--2/5+1--3/5

H24
3 tháng 7 2022 lúc 15:30

\(x:\dfrac{1}{5}=7\\ x=7\times\dfrac{1}{5}\\ x=\dfrac{7}{5}\\ ~\\ x\times\dfrac{2}{3}=9\\ x=9:\dfrac{2}{3}\\ x=\dfrac{27}{2}\\ ~\\ 1\dfrac{3}{7}+x=2\dfrac{1}{5}\\ \dfrac{10}{7}+x=\dfrac{11}{5}\\ x=\dfrac{11}{5}-\dfrac{10}{7}\\ x=\dfrac{27}{35}\\ ~\\ 4\dfrac{1}{3}-x=2\dfrac{2}{5}+1\dfrac{3}{5}\\ \dfrac{13}{3}-x=4\\ x=\dfrac{13}{3}-4\\ x=\dfrac{1}{3}\)

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H24
3 tháng 7 2022 lúc 15:31

`x : 1/5 = 7`

`x=7 xx 1/5`

`x=7/5`

__________

`x xx 2/3 = 9`

`x=9 : 2/3`

`x=9xx3/2`

`x=13,5`

_____________________

`1 3/7 + x = 2 1/5`

`x = 2 1/5 - 1 3/7`

`x= 1 (-8)/35`

`x=27/35`

_________________

`4 1/3 - x = 2 2/5 + 1 3/5`

`4 1/3 - x = 3 5/5`

`4 1/3 - x = 4`

`13/3 - x = 4`

`x=13/3-4`

`x=1/3`

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NH
3 tháng 7 2022 lúc 15:34

\(x:\dfrac{1}{5}=7\)

\(x=7\times\dfrac{1}{5}\)

\(x=\dfrac{7}{5}\)


\(x\times\dfrac{2}{3}=9\)

\(x=9:\dfrac{2}{3}\)

\(x=\dfrac{27}{2}\)


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

\(\dfrac{10}{7}+x=\dfrac{11}{5}\)

\(x=\dfrac{11}{5}-\dfrac{10}{7}\)

\(x=\dfrac{27}{35}\)


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

\(\dfrac{13}{3}-x=\dfrac{12}{5}+\dfrac{8}{5}\)

\(\dfrac{13}{3}-x=4\)

\(x=\dfrac{13}{3}-4\)

\(x=\dfrac{1}{3}\)

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H24
3 tháng 7 2022 lúc 15:37

x : 1/5=7

x        = 7 x 1/5

x        = 7/5

X x 2/3 = 9

x          = 9 : 2/3 

x          = 9 x 3/2

x          = 27/2

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

10/7 + x = 11/5

           x = 11/5 - 10/7

           x = 27/35

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

13/3 - x = (2+1)+(2/5+1/5) = \(3\dfrac{3}{5}\) = 18/5

          x = 13/3 - 18/5

          x = 65/15 - 54/15

          x = 11/15

          

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