4/5+5/7:x=1/6 cái gạch chéo là phân số

$\dfrac{4}{5}$  `+` $\dfrac{5}{7}$ `÷` `x` `=` $\dfrac{1}{6}$ 

`⇒` $\dfrac{5}{7}$ `÷` `x` `=` $\dfrac{1}{6}$ `-` $\dfrac{4}{5}$  

`⇒` $\dfrac{5}{7}$ `÷` `x` `=` `-` $\dfrac{19}{30}$ 

`⇒` `x`                             `=` `-` $\dfrac{19}{30}$  `÷` $\dfrac{5}{7}$

`⇒` `x`                             `=` `-` $\dfrac{150}{133}$

$\text{Vậy x = - $\dfrac{150}{133}$ }$

$#Zen$

`4/5 + 5/7 : x = 1/6`

`⇒ 5/7 : x = 1/6 - 4/5`

`⇒ 5/7 : x = ( - 19 )/30`

`⇒ x = 5/7 : ( - 19 )/30`

`⇒ x = - 150/133`

Vậy `, x = - 150/133 .`