a: \(\Leftrightarrow\left\{{}\begin{matrix}\dfrac{15}{3x+y}+\dfrac{12}{2x-3y}=-6\\\dfrac{15}{3x+y}-\dfrac{25}{2x-3y}=105\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}\dfrac{37}{2x-3y}=-111\\\dfrac{4}{2x-3y}+\dfrac{5}{3x+y}=-2\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}2x-3y=-\dfrac{1}{3}\\3x+y=\dfrac{1}{2}\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2x-3y=-\dfrac{1}{3}\\9x+3y=\dfrac{3}{2}\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}11x=\dfrac{7}{6}\\3x+y=\dfrac{1}{2}\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{7}{66}\\y=\dfrac{2}{11}\end{matrix}\right.\)
