Giải thích các bước giải:
Ta có:
\(\begin{array}{l}
a,\\
\left| x \right| + x = 10\,\,\,\,\,\left( 1 \right)\\
TH1:\,\,\,\,x \ge 0 \Rightarrow \left| x \right| = x\\
\left( 1 \right) \Leftrightarrow x + x = 10\\
\Leftrightarrow x = 5\,\,\,\,\,\left( {t/m} \right)\\
TH1:\,\,\,\,x < 0 \Rightarrow \left| x \right| = - x\\
\left( 1 \right) \Leftrightarrow \left( { - x} \right) + x = 10\\
\Leftrightarrow 0 = 10\,\,\,\,\,\,\left( L \right)\\
b,\\
\left| x \right| - x = 16\,\,\,\,\,\,\,\,\,\,\,\left( 2 \right)\\
TH1:\,\,\,\,\,x \ge 0 \Rightarrow \left| x \right| = x\\
\left( 2 \right) \Leftrightarrow x - x = 16\\
\Leftrightarrow 0 = 16\,\,\,\,\,\,\left( L \right)\\
TH2:\,\,\,\,\,x < 0 \Rightarrow \left| x \right| = - x\\
\left( 1 \right) \Leftrightarrow \left( { - x} \right) - x = 16\\
\Leftrightarrow - 2x = 16\\
\Leftrightarrow x = - 8\,\,\,\,\,\left( {t/m} \right)\\
c,\\
{\left( {2x - 3} \right)^n} = {5^n}\\
\Leftrightarrow 2x - 3 = 5\\
\Leftrightarrow x = 4
\end{array}\)
(Do n là số tự nhiên lẻ).
