Question

Answer 1

`#ava`

Bài `4` : Tìm `x:`

`a)-2/5+5/6(x-2/3)=-4/15`

`5/6(x−2/3)=−4/15+2/5`

`5/6(x−2/3)=−4/15+6/15`

`5/6(x−2/3)=2/15`

`x−2/3=2/15:5/6`

`x−2/3=12/75`

`x=12/75+2/3`

`x=62/75`

`b)−x−1/9=−2/45`

`−x=−2/45+1/9`

`−x=1/15`

`->x=−1/15`

`c)17/18−(x+7/12)=1/9`

`x+7/12=17/18−1/9`

`x+7/12=5/6`

`x=5/6−7/12`

`x=1/4`

`d)13/15-(13/21+x).7/2=7/10`

`(13/21+x).7/12=1/6`

`13/21+x=2/7`

`x=-1/3`

Answer 2

`a)-2/5+5/6(x-2/3)=-4/15`

`5/6(x-2/3)=-4/15+2/5=2/15`

`x-2/3=2/15:5/6=4/25`

`x=4/25+2/3=62/75`

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`b)-x-1/9=-2/45`

`-x=-2/45+1/9`

`-x=1/15`

`x=-1/15`

__________________________________________________________

`c)17/18-(x+7/12)=1/9`

`x+7/12=17/18-1/9=5/6`

`x=5/6-7/12=1/4`

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`d)13/15-(13/21+x)xx7/12=7/10`

`(13/21+x)xx7/12=13/15-7/10=1/6`

`13/21+x=1/6:7/12=2/7`

`x=2/7-13/21=-1/3`

Answer 3

a: \(\Leftrightarrow\left(x-\dfrac{2}{3}\right)\cdot\dfrac{5}{6}=\dfrac{-4}{15}+\dfrac{2}{5}=\dfrac{-4+6}{15}=\dfrac{2}{15}\)

=>x-2/3=4/25

hay x=62/75

b: \(\Leftrightarrow x+\dfrac{1}{9}=\dfrac{2}{45}\)

=>x=2/45-1/9=2/45-5/45=-3/45=-1/15

c: \(\dfrac{17}{18}-\left(x+\dfrac{7}{12}\right)=\dfrac{1}{9}\)

=>x+7/12=17/18-1/9=17/18-2/18=15/18=5/6

=>x=5/6-7/12=10/12-7/12=1/4

d: \(\Leftrightarrow\left(x+\dfrac{13}{21}\right)\cdot\dfrac{7}{12}=\dfrac{13}{15}-\dfrac{7}{10}=\dfrac{26-21}{30}=\dfrac{1}{6}\)

=>x+13/21=1/6:7/12=1/6x12/7=12/42=2/7

=>x=2/7-13/21=-1/21