$\text{a) $\dfrac{1}{4}$ - (x + $\dfrac{1}{2}$) = $\dfrac{3}{5}$}$
$\text{x + $\dfrac{1}{2}$ = $\dfrac{1}{4}$ - $\dfrac{3}{5}$}$
$\text{x + $\dfrac{1}{2}$ = $\dfrac{1}{4}$ - $\dfrac{3}{5}$}$
$\text{x + $\dfrac{1}{2}$ = $\dfrac{5}{20}$ - $\dfrac{12}{20}$}$
$\text{x + $\dfrac{1}{2}$ = $\dfrac{-7}{20}$ }$
$\text{x = $\dfrac{-7}{20}$ - $\dfrac{1}{2}$ }$
$\text{x = $\dfrac{-7}{20}$ - $\dfrac{10}{20}$ }$
$\text{x = $\dfrac{-17}{20}$ }$
$\text{b) |x - 1,4| = 2,6}$
$\text{x - 1,4 = 2,6 hoặc x - 1,4 = -2,6}$
$\text{TH1: x - 1,4 = 2,6}$
$\text{ x = 2,6 + 1,4}$
$\text{ x = 4}$
$\text{TH2: x - 1,4 = -2,6}$
$\text{ x = -2,6 + 1,4}$
$\text{ x = -1,2}$
$\text{Vậy x ∈ {4; -1,2}}$
