Đáp án:
\(\left[ \begin{array}{l}
x = 1\\
x = - 21
\end{array} \right.\)
Giải thích các bước giải:
\(\begin{array}{l}
a)\left| {x - 13} \right| - \left| {2x + 9} \right| = 1\\
\to \left| {x - 13} \right| = 1 + \left| {2x + 9} \right|\\
\to \left[ \begin{array}{l}
x - 13 = 1 + 2x + 9\left( {DK:x \ge 13} \right)\\
- x + 13 = 1 + 2x + 9\left( {DK:13 > x \ge - \dfrac{9}{2}} \right)\\
- x + 13 = 1 - 2x - 9\left( {DK: - \dfrac{9}{2} > x} \right)
\end{array} \right.\\
\to \left[ \begin{array}{l}
x = - 23\left( l \right)\\
3x = 3\\
x = - 21
\end{array} \right.\\
\to \left[ \begin{array}{l}
x = 1\\
x = - 21
\end{array} \right.
\end{array}\)
