Ta có: |x - $\frac{4}{5}$| = $\frac{3}{4}$
⇔ \(\left[ \begin{array}{l}x-\frac{4}{5}=\frac{3}{4}\\x-\frac{4}{5}=-\frac{3}{4}\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x=\frac{3}{4}+\frac{4}{5}\\x=-\frac{3}{4}+\frac{4}{5}\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x=\frac{31}{20}\\x=\frac{1}{20}\end{array} \right.\)