\(4^{961}+23^{2005}-19^{1997}\)
\(=4^{960}.4+23^{2004}.23-19^{1996}.19\)
\(=\left(4^2\right)^{480}.4+\left(23^4\right)^{501}.23-\left(19^2\right)^{998}.19\)
\(=\overline{\left(...6\right)}^{480}.4+\overline{\left(...1\right)}^{501}.23-\overline{\left(...1\right)}^{998}.19\)
\(=\overline{\left(...6\right)}.4+\overline{\left(...1\right)}.23-\overline{\left(...1\right)}.19\)
\(=\overline{\left(...4\right)}+\overline{\left(...3\right)}-\overline{\left(...9\right)}\)
\(=\overline{\left(...7\right)}-\overline{\left(...9\right)}\)
\(=\overline{...8}\)