a) Ta có: (x+4)(y+5)=3
⇒x+4; y+5∈Ư(3)
hay x+4; y+5∈{1;3;-1;-3}
*Trường hợp 1:
\(\left\{{}\begin{matrix}x+4=1\\y+5=3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-3\\y=-2\end{matrix}\right.\)(tm)
*Trường hợp 2:
\(\left\{{}\begin{matrix}x+4=3\\y+5=1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-1\\y=-4\end{matrix}\right.\)(tm)
*Trường hợp 3:
\(\left\{{}\begin{matrix}x+4=-1\\y+5=-3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-5\\y=-8\end{matrix}\right.\)(tm)
*Trường hợp 4:
\(\left\{{}\begin{matrix}x+4=-3\\y+5=-1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-7\\y=-6\end{matrix}\right.\)(tm)
Vậy: x∈{-3;-1;-5;-7} và y∈{-2;-4;-8;-6}
b) Ta có: (x+2)(y-5)=-3
⇒x+2;y-5∈Ư(-3)
hay x+2; y-5∈{1;-3;-1;-3}
*Trường hợp 1:
\(\left\{{}\begin{matrix}x+2=1\\y-5=-3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-1\\y=2\end{matrix}\right.\)(tm)
*Trường hợp 2:
\(\left\{{}\begin{matrix}x+2=-3\\y-5=1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-5\\y=4\end{matrix}\right.\)(tm)
*Trường hợp 3:
\(\left\{{}\begin{matrix}x+2=-1\\y-5=3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-3\\y=8\end{matrix}\right.\)(tm)
*Trường hợp 4:
\(\left\{{}\begin{matrix}x+2=3\\y-5=-1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=1\\y=4\end{matrix}\right.\)(tm)
Vậy: x∈{-1;-5;-3;1} và y∈{2;4;8}
