Giải thích các bước giải:
Ta có:
\(\begin{array}{l}
a,\\
2.\left| {1 - 2x} \right| - 1 = 3\\
\Leftrightarrow 2.\left| {1 - 2x} \right| = 4\\
\Leftrightarrow \left| {1 - 2x} \right| = 2\\
\Leftrightarrow \left[ \begin{array}{l}
1 - 2x = 2\\
1 - 2x = - 2
\end{array} \right. \Leftrightarrow \left[ \begin{array}{l}
2x = - 1\\
2x = 3
\end{array} \right. \Leftrightarrow \left[ \begin{array}{l}
x = - \dfrac{1}{2}\\
x = \dfrac{3}{2}
\end{array} \right.\\
b,\\
\left| {\left| {x - \dfrac{1}{2}} \right| - 3} \right| = 3\\
\Leftrightarrow \left[ \begin{array}{l}
\left| {x - \dfrac{1}{2}} \right| - 3 = - 3\\
\left| {x - \dfrac{1}{2}} \right| - 3 = 3
\end{array} \right. \Leftrightarrow \left[ \begin{array}{l}
\left| {x - \dfrac{1}{2}} \right| = 0\\
\left| {x - \dfrac{1}{2}} \right| = 6
\end{array} \right.\\
\Leftrightarrow \left[ \begin{array}{l}
x - \dfrac{1}{2} = 0\\
x - \dfrac{1}{2} = 6\\
x - \dfrac{1}{2} = - 6
\end{array} \right. \Leftrightarrow \left[ \begin{array}{l}
x = \dfrac{1}{2}\\
x = \dfrac{{13}}{2}\\
x = - \dfrac{{11}}{2}
\end{array} \right.
\end{array}\)
