`a) ( - 3 )/7 + x = ( - 1 )/2 : 7`

`⇔ ( - 3 )/7 + x = ( - 1 )/14`

`⇔ x = ( - 1 )/14 - ( - 3 )/7`

`⇔ x = 5/14`

Vậy `, x = 5/14 .`

`b) 3x - ( 1/6 - 1/2 x ) = - 1 2/3`

`⇔ 3x - 1/6 + 1/2 x = ( - 5 )/3`

`⇔ x . ( 3 - 1/2 ) = ( - 5 )/3 + 1/6`

`⇔ x . 5/2 = ( - 3 )/2`

`⇔ x = ( - 3 )/2 : 5/2`

`⇔ x = ( - 3 )/5`

Vậy `, x = ( - 3 )/5 .`

`c) 2 4/5 . x - 0,2 : 4/5 = 7/8`

`⇔ 14/5 . x - 1/4 = 7/8`

`⇔ 14/5 . x = 7/8 + 1/4`

`⇔ 14/5 . x = 9/8`

`⇔ x = 9/8 : 14/5`

`⇔ x = 45/112`

Vậy `, x = 45/112 .`

`d) 1/4 + 1/3 : | 2x - 1 | = 11/12`

`⇔ 1/3 : | 2x - 1 | = 11/12 - 1/4`

`⇔ 1/3 : | 2x - 1 | = 2/3`

`⇔ | 2x - 1 | = 1/3 : 2/3`

`⇔ | 2x - 1 | = 1/2`

`⇔` $\left[\begin{matrix}2x - 1 = \frac{1}{2}\\2x - 1 = \frac{- 1}{2}\end{matrix}\right.$

`⇔` $\left[\begin{matrix}2x = \frac{3}{2}\\2x = \frac{1}{2}\end{matrix}\right.$

`⇔` $\left[\begin{matrix}x = \frac{3}{4}\\x = \frac{1}{4}\end{matrix}\right.$

Vậy `, x ∈ { 3/4 ; 1/4 } .`

`e) 3/5 - ( 2 1/5 - x )^2 = 6/25`

`⇔ ( 11/5 - x )^2 = 3/5 - 6/25`

`⇔ ( 11/5 - x )^2 = 9/25`

`⇔` $\left[\begin{matrix}( \frac{11}{5} - x )^2 = ( \frac{3}{5} )^2\\( \frac{11}{5} - x )^2 = ( \frac{- 3}{5} )^2\end{matrix}\right.$

`⇔` $\left[\begin{matrix}\frac{11}{5} - x = \frac{3}{5}\\\frac{11}{5} - x = \frac{- 3}{5}\end{matrix}\right.$

`⇔` $\left[\begin{matrix}x = \frac{8}{5}\\x = \frac{14}{5}\end{matrix}\right.$

Vậy `, x ∈ { 8/5 ; 14/5 } .`

$\text{Đáp án+Giải thích các bước giải:}$

$a)$ $\dfrac{-3}{7}$ $+x=$ $\dfrac{-1}{2}$ $:7$
⇔ $\dfrac{7x-3}{7}$ = $\dfrac{-1}{2}$.$\dfrac{1}{7}$ = $\dfrac{-1}{14}$
⇔ $\dfrac{14x-6}{14}$ = $\dfrac{-1}{14}$
$⇔ 14x-6=-1 ⇔ 14x=5 ⇔ x=$ $\dfrac{5}{14}$ 
$b)$ $3x-($ $\dfrac{1}{6}$ - $\dfrac{x}{2}$ ) = $\dfrac{-1}{3}$
⇔ $\dfrac{18x}{6}$-$\dfrac{1-3x}{6}$ = $\dfrac{-2}{6}$
$⇔ 18x-1+3x=-2$
$⇔ 21x=-1$
$⇔ x=$ $\dfrac{-1}{21}$ 
$c)$ $\dfrac{14x}{5}$ - $\dfrac{1}{5}$ . $\dfrac{5}{4}$ = $\dfrac{7}{8}$ 
⇔ $\dfrac{14x}{5}$ - $\dfrac{1}{4}$ = $\dfrac{7}{8}$ 
⇔ $\dfrac{112x}{40}$ - $\dfrac{10}{40}$ = $\dfrac{35}{40}$ 
$⇔ 112x-10=35$
$⇔ 112x=45$
$⇔ x=$ $\dfrac{45}{112}$ 
$d)$ $\dfrac{1}{4}$ + $\dfrac{1}{3}$ . $\dfrac{1}{|2x-1|}$ = $\dfrac{11}{12}$
⇔ $\dfrac{3|2x-1|}{12|2x-1|}$ + $\dfrac{4}{12|2x-1|}$ = $\dfrac{11|2x-1|}{12|2x-1|}$
$⇔ 3|2x-1|+4=11|2x-1|$
$⇔ 11|2x-1|-3|2x+1|=4$
$⇔ 8|2x+1|=4$
$⇔ 2|2x+1|=1$
$⇔ |2x+1|=$ $\dfrac{1}{2}$ 
$⇔ 2x+1=$ $\dfrac{1}{2}$ $; 2x+1=$ $\dfrac{-1}{2}$ 
$⇔ x=$ $\dfrac{-1}{4}$ $; x=$ $\dfrac{-3}{4}$ 
$e)$ $\dfrac{3}{5}$ - ($\dfrac{11}{5}$ $-x)²$=$\dfrac{6}{25}$ 
⇔ ($\dfrac{11}{5}$ $-x)²$= $\dfrac{3}{5}$-$\dfrac{6}{25}$ =$\dfrac{15}{25}$ - $\dfrac{6}{25}$ 
⇔ ($\dfrac{11}{5}$ $-x)²$ = $\dfrac{9}{25}$ 
$TH1:$ $\dfrac{11}{5}$ $-x =$ $\dfrac{3}{5}$ 
$⇔ x=$ $\dfrac{11}{5}$-$\dfrac{3}{5}$ =$\dfrac{8}{5}$ 
$TH2:$ $\dfrac{11}{5}$ $-x =$ $\dfrac{-3}{5}$
$⇔ x=$ $\dfrac{11}{5}$ $-$ $\dfrac{-3}{5}$=$\dfrac{14}{5}$