a/ \(x+2y-3=5\)
\(\Rightarrow x+2y=8\)
Xét từng TH ta có: (chỉ xét những TH t/m)
+) \(\left\{{}\begin{matrix}x=0\\2y=8\Rightarrow y=4\end{matrix}\right.\)
+) \(\left\{{}\begin{matrix}x=2\\2y=6\Rightarrow y=3\end{matrix}\right.\)
+) \(\left\{{}\begin{matrix}x=4\\2y=4\Rightarrow y=2\end{matrix}\right.\)
+) \(\left\{{}\begin{matrix}x=6\\2y=2\Rightarrow y=1\end{matrix}\right.\)
+) \(\left\{{}\begin{matrix}x=8\\2y=0\Rightarrow y=0\end{matrix}\right.\)
Vậy...................................................
b/ \(\left(x-2\right).\left(y+5\right)=-7\)
\(\Rightarrow\left(x-5\right)\inƯ_{\left(-7\right)}\) ; \(\left(y+5\right)\inƯ_{\left(-7\right)}\)
Xét từng TH..................(tự ghi ra)
\(\Rightarrow x\in\left\{-5;1;3;9\right\}\)
\(y\in\left\{-12;-6;-4;2\right\}\)
c/ \(\left(2x-1\right)\left(y+3\right)=-6\)
\(\rightarrow\) cách lm tương tự ý b