\[\text{a\ }и\ b - данные\ числа:\]
\[a + b = ab;\ \ \ \ \ a,b \in Z;\]
\[ab - a = b\]
\[a(b - 1) = b\]
\[a = \frac{b}{b - 1} \in Z.\]
\[b - 1 = - 1\text{\ \ \ }\]
\[b = 0.\text{\ \ \ }\]
\[b - 1 = 1\]
\[b = 2.\text{\ \ \ }\]
\[a = \frac{0}{0 - 1} = 0\]
\[a = \frac{2}{2 - 1} = 2.\]
\[Ответ:\ \ (0;\ 0);\ (2;\ 2).\]