[tex]\begin{cases}x+2y=15\\2x-3y=5\end{cases}\Leftrightarrow \begin{cases}2x+4y=30\\2x-3y=5\end{cases}\Leftrightarrow 7y=25\Rightarrow (x,y)=\left ( \frac{55}{7},\frac{25}{7} \right )[/tex]