Вопрос:

Ответ:

\[\left( x^{4} \right)^{3} \cdot \ *\ = - x^{15}\]

\[x^{12} \cdot \ *\ = - x^{15}\]

\[*\ = - x^{15}\ :x^{12}\]

\[* = - x^{15 - 12}\]

\[*\ = - x^{3}.\]