\[\boxed{\text{6.71.}}\]
\[\textbf{а)}\ 25x - (14x + 8x) = 2\ 427\ \]
\[25x - 22x = 2\ 427\]
\[3x = 2\ 427\]
\[x = 2\ 427\ :3\]
\[x = 809.\ \]
\[Ответ:809.\ \]
\[\textbf{б)}\ 23y - (25y - 11y) = 7\ 245\]
\[23y - 14y = 7\ 245\]
\[9y = 7\ 245\]
\[y = 7\ 245\ :9\]
\[y = 805.\ \]
\[Ответ:805.\]