Công thức:
$|A|≥B $
$\(\left[ \begin{array}{l}A\geq B\\A\leq -B\end{array} \right.\) $
$|2x-1|\geq x+2$
$<=> $\(\left[ \begin{array}{l}2x-1\geq x+2\\2x-1\leq -x-2\end{array} \right.\)
$<=> $\(\left[ \begin{array}{l}x\geq 3\\x\leq \dfrac{1}{3}\end{array} \right.\)
$S= (-∞; \dfrac{1}{3}]∪[3;+∞)$