Đáp án:
$\text{a) x + $\dfrac{4}{15}$ = $\dfrac{-3}{10}$}$
$\text{ => x = $\dfrac{-3}{10}$ - $\dfrac{4}{15}$}$
$\text{=> x = $\dfrac{-17}{30}$}$
$\text{Vậy x= $\dfrac{-17}{30}$}$
$\text{b) (2x+$\dfrac{1}{2}$) ($\dfrac{4}{5}$ - x ) =0}$
$\text{=>\(\left[ \begin{array}{l}2x+\dfrac{1}{2}=0\\\dfrac{4}{5} - x =0\end{array} \right.\) }$
$\text{=>\(\left[ \begin{array}{l}x=\dfrac{-1}{4}\\x=\dfrac{4}{5}\end{array} \right.\) }$
Vậy x= { $\dfrac{-1}{4}$ ; $\dfrac{4}{5}$}
