\[\ (4 + 9x)(7 - 2x) = 0\]
\[4 + 9x = 0\ \ \ \ \ \ \ \ \ 7 - 2x = 0\]
\[9x = - 4\ \ \ \ \ \ \ \ \ \ \ \ - 2x = - 7\]
\[Ответ:\ \ x = - \frac{4}{9}\ \ \ \ и\ \ = 3,5.\]