Đáp án:
\(\left[ \begin{array}{l}
C = x - 4\\
C = - x + 4
\end{array} \right.\)
Giải thích các bước giải:
\(\begin{array}{l}
DK:x \ne 5\\
C = \left( {\sqrt {{{\left( {x - 5} \right)}^2}} } \right) - \dfrac{{\left( {\sqrt {{{\left( {5 - x} \right)}^2}} } \right)}}{{5 - x}}\\
= \left| {x - 5} \right| - \dfrac{{\left| {5 - x} \right|}}{{5 - x}}\\
\to \left[ \begin{array}{l}
C = x - 5 - \dfrac{{ - \left( {5 - x} \right)}}{{5 - x}}\left( {DK:x > 5} \right)\\
C = - x + 5 - \dfrac{{\left( {5 - x} \right)}}{{5 - x}}\left( {DK:x < 5} \right)
\end{array} \right.\\
\to \left[ \begin{array}{l}
C = x - 5 + 1\\
C = - x + 5 - 1
\end{array} \right.\\
\to \left[ \begin{array}{l}
C = x - 4\\
C = - x + 4
\end{array} \right.
\end{array}\)
