a/ \(\left|x-\frac{1}{3}\right|=2\frac{1}{5}\)
\(\left|x-\frac{1}{3}\right|=\frac{11}{5}\)
\(\Rightarrow\left[{}\begin{matrix}x-\frac{1}{3}=\frac{11}{5}\\x-\frac{1}{3}=\frac{-11}{5}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\frac{11}{5}+\frac{1}{3}\\x=\frac{-11}{5}+\frac{1}{3}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\frac{33}{15}+\frac{5}{15}\\x=\frac{-33}{15}+\frac{5}{15}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\frac{38}{15}\\x=\frac{28}{15}\end{matrix}\right.\)
Vậy:
c/
\(\left|x+\frac{1}{4}\right|-\frac{3}{4}=5\%\)
\(\left|x+\frac{1}{4}\right|-\frac{3}{4}=\frac{1}{20}\)
\(\left|x+\frac{1}{4}\right|=\frac{1}{20}+\frac{15}{20}\)
\(\left|x+\frac{1}{4}\right|=\frac{4}{5}\)
\(\Rightarrow\left[{}\begin{matrix}x+\frac{1}{4}=\frac{4}{5}\\x+\frac{1}{4}=\frac{-4}{5}\end{matrix}\right.\)
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