Giải các hệ phương trình sau:
a, \(\left\{{}\begin{matrix}5x+3y=8xy\\3x+2y=5xy\end{matrix}\right.\)
b, \(\left\{{}\begin{matrix}-x+y=xy\\4x+3y=5xy\end{matrix}\right.\)
c, \(\left\{{}\begin{matrix}2x-y=5\\\left(x+y+2\right)\left(x+2y-5\right)=0\end{matrix}\right.\)