Đáp án:
\(\left\{ \begin{array}{l}
x = 9\\
y = 16\\
z = 19
\end{array} \right.\)
Giải thích các bước giải:
\(\begin{array}{l}
\left\{ \begin{array}{l}
\dfrac{{x - 3}}{3} = \dfrac{{y - 2}}{7}\\
\dfrac{{x - 3}}{3} = \dfrac{{z - 1}}{9}\\
3x + 2y - z = 40
\end{array} \right.\\
\to \left\{ \begin{array}{l}
7x - 21 = 3y - 6\\
3x - 9 = z - 1\\
3x + 2y - z = 40
\end{array} \right.\\
\to \left\{ \begin{array}{l}
y = \dfrac{{7x - 15}}{3}\\
z = 3x - 8\\
3x + 2.\dfrac{{7x - 15}}{3} - 3x + 8 = 40
\end{array} \right.\\
\to \left\{ \begin{array}{l}
y = \dfrac{{7x - 15}}{3}\\
z = 3x - 8\\
\dfrac{{14x - 30}}{3} = 32
\end{array} \right.\\
\to \left\{ \begin{array}{l}
y = \dfrac{{7x - 15}}{3}\\
z = 3x - 8\\
14x - 30 = 96
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x = 9\\
y = 16\\
z = 19
\end{array} \right.
\end{array}\)
