Đáp án+giải thích các bước giải:
|$\dfrac{7}{2} + x | - \dfrac{2}{5} = \dfrac{1}{5}$
|$\dfrac{7}{2} + x | = \dfrac{1}{5} + \dfrac{2}{5}$
|$\dfrac{7}{2} + x | = \dfrac{3}{5}$
TH1:
$\dfrac{7}{2} + x = \dfrac{3}{5}$
$x = \dfrac{3}{5} - \dfrac{7}{2}$
$x = \dfrac{-29}{10}$
TH2:
$\dfrac{7}{2} + x = \dfrac{-3}{5}$
$x = (\dfrac{-3}{5}) - \dfrac{7}{2}$
$x = \dfrac{-41}{10}$
