\(17.\left\{{}\begin{matrix}\left(m-1\right)x-y=m+2\\2x-y=3\end{matrix}\right.\) \(\Leftrightarrow\dfrac{m-1}{2}\ne1\Leftrightarrow m\ne3\)
\(18..\sqrt{2}x^2-2\sqrt{6}x-\sqrt{10}=0\Rightarrow\left\{{}\begin{matrix}S=x1+x2=\dfrac{-b}{a}=\dfrac{2\sqrt{6}}{\sqrt{2}}=2\sqrt{3}\\P=x1x2=\dfrac{c}{a}=\dfrac{-\sqrt{10}}{\sqrt{2}}=-\sqrt{5}\end{matrix}\right.\)