a) \(\left|x-\dfrac{1}{2}\right|=\dfrac{3}{4}\)
\(\Leftrightarrow\left[{}\begin{matrix}x-\dfrac{1}{2}=\dfrac{3}{4}\\x-\dfrac{1}{2}=-\dfrac{3}{4}\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{4}+\dfrac{1}{2}\\x=-\dfrac{3}{4}+\left(-\dfrac{1}{2}\right)\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{4}\\x=-\dfrac{1}{4}\end{matrix}\right.\)
Vậy \(x=\dfrac{5}{4}\) hoặc \(x=-\dfrac{1}{4}\)
b) \(\left|\dfrac{4}{3}+x\right|=\dfrac{2}{5}\)
\(\Leftrightarrow\left[{}\begin{matrix}\dfrac{4}{3}+x=\dfrac{2}{5}\\\dfrac{4}{3}+x=-\dfrac{2}{5}\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{2}{5}-\dfrac{4}{3}\\x=-\dfrac{2}{5}-\dfrac{4}{3}\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{14}{15}\\x=-\dfrac{26}{15}\end{matrix}\right.\)
Vậy \(x=-\dfrac{14}{15}\) hoặc \(x=-\dfrac{26}{15}\)
