d: \(\Leftrightarrow\left\{{}\begin{matrix}-6x-18y+24z=18\\6x+8y-4z=10\\6x+3y+6z=12\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}-10y+20z=28\\-15y+30z=30\\-x-3y+4z=3\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}-30y+60z=84\\-30y+60z=60\\-x-3y+4z=3\end{matrix}\right.\)
Vậy: PT vô nghiệm