\(-3{\log _{0,25}}x \le 6\left| {:\left( {-3 < 0} \right)\,\,\,\,\,\,\, \Leftrightarrow \,\,\,\,\,\,\,{{\log }_{0,25}}x \ge -2\,\,\,\,\,\,\, \Leftrightarrow } \right.\)
\( \Leftrightarrow \,\,\,\,\,\,\,{\log _{0,25}}x \ge {\log _{0,25}}16\,\,\,\,\,\,\, \Leftrightarrow \,\,\,\,\,\,\,\left\{ {\begin{array}{*{20}{c}}{x \le 16,}\\{x > 0\,\,\,}\end{array}\,\,\,\,\,\,\,\,\, \Leftrightarrow \,\,\,\,\,\,\,\,x\, \in \,\left( {0;16} \right].} \right.\)
Целые решения: \(1,\,\,2,\,\,3,…,16.\) Их сумма равна: \(\dfrac{{1 + 16}}{2} \cdot 16 = 136.\)
Ответ: 136.