\(\boxed{\mathbf{1047\ (1038).}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\)
\[1)\ 3x = 0\]
\[x = 0\]
\(Ответ:0.\)
\[2) - 6,8 \cdot (x - 4) = 0\]
\[x - 4 = 0\]
\[x = 4\]
\[Ответ:4.\]
\[3)\ (x + 7,2)(x - 8,1) = 0\]
\[x + 7,2 = 0\ \ \ \ \ \ \ x - 8,1 = 0\]
\[x = - 7,2\ \ \ \ \ \ \ \ \ \ \ x = 8,1\]
\[Ответ:\ - 7,2;8,1.\]
\[4) - 5|x| = 0\]
\[|x| = 0\]
\[x = 0\]
\[Ответ:0.\]