\[(6y + 15)(2,4 - 0,8y) = 0\]
\[6y + 15 = 0\ \ \ \ \ \ \ \ 2,4 - 0,8y = 0\]
\[6y = - 15\ \ \ \ \ \ \ \ \ \ \ \ 0,8y = 2,4\]
\[y = - \frac{15}{6}\ \ \ \ \ \ \ \ \ \ \ \ \ y = \frac{24}{8}\]
\[y = - 2,5\ \ \ \ \ \ \ \ \ \ \ \ \ \ y = 3\]
\[Ответ:y = - 2,5;\ \ y = 3.\]