\(a,2xy+4y-x=5\\ \Leftrightarrow2y\left(x+2\right)-\left(x+2\right)=3\\ \Leftrightarrow\left(x+2\right)\left(2y-1\right)=3\\ Vìx,y\in Z\\ \Rightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x+2=1\\2y-1=3\end{matrix}\right.\\\left\{{}\begin{matrix}x+2=-1\\2y-1=-3\end{matrix}\right.\end{matrix}\right.và\left[{}\begin{matrix}\left\{{}\begin{matrix}x+2=3\\2y-1=1\end{matrix}\right.\\\left\{{}\begin{matrix}x+2=-3\\2y-1=-1\end{matrix}\right.\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x=-1\\y=2\end{matrix}\right.\\\left\{{}\begin{matrix}x=-3\\y=-1\end{matrix}\right.\end{matrix}\right.và\left[{}\begin{matrix}\left\{{}\begin{matrix}x=1\\y=1\end{matrix}\right.\\\left\{{}\begin{matrix}x=-5\\y=0\end{matrix}\right.\end{matrix}\right.\\ Vậy...........\)
\(b,2x+y=xy-3\\ \Leftrightarrow2x+y-xy+3=0\\ \Leftrightarrow x\left(2-y\right)-\left(2-y\right)+5=0\\ \Leftrightarrow\left(2-y\right)\left(x-1\right)=-5\\ \Leftrightarrow\left(y-2\right)\left(x-1\right)=5\\ Rồibntựxétnhé!!!!\)