Đáp án$\quad+\quad$Giải thích:

`|x-3/4|-1/2=(-1)/5`

`<=>|x-3/4|=(-1)/5+1/2`

`<=>|x-3/4|=(-2)/10+5/10`

`<=>|x-3/4|=((-2)+5)/10`

`<=>|x-3/4|=3/10`

`<=>x-3/4=+-3/10`

`<=>`\(\left[ \begin{array}{l}x-\dfrac{3}{4}=\dfrac{3}{10}\\x-\dfrac{3}{4}=\dfrac{-3}{10}\end{array} \right.\) 

`<=>`\(\left[ \begin{array}{l}x=\dfrac{3}{10}+\dfrac{3}{4}\\x=\dfrac{-3}{10}+\dfrac{3}{4}\end{array} \right.\) 

`<=>`\(\left[ \begin{array}{l}x=\dfrac{12}{40}+\dfrac{30}{40}\\x=\dfrac{-12}{40}+\dfrac{30}{40}\end{array} \right.\) 

`<=>`\(\left[ \begin{array}{l}x=\dfrac{12+30}{40}\\x=\dfrac{(-12)+30}{40}\end{array} \right.\) 

`<=>`\(\left[ \begin{array}{l}x=\dfrac{42}{40}\\x=\dfrac{18}{40}\end{array} \right.\) 

`<=>`\(\left[ \begin{array}{l}x=\dfrac{21}{20}\\x=\dfrac{9}{20}\end{array} \right.\) 

Vậy `x=21/20;x=9/20`

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

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

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

`|x-3/4|=3/10`

`x-3/4=+-3/10`

$TH1:$ `x-3/4=3/10`

`x=3/10+3/4`

`x=21/20`

$TH2:$ `x-3/4=-3/10`

`x=-3/10+3/4`

`x=9/20`

Vậy `x \in {21/20;9/20}`