\(\left\{{}\begin{matrix}x-2y=-3\\5x+4y=6\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2x-4y=-6\\5x+4y=6\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}7x=0\\x-2y=-3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0\\y=\dfrac{x+3}{2}=\dfrac{3}{2}\end{matrix}\right.\\ \Rightarrow S=\left\{\left(0;\dfrac{3}{2}\right)\right\}\)