\[\boxed{\text{538\ (538).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[\textbf{а)}\ ( - 1)^{n} \cdot ( - 1)^{n} = ( - 1)^{2n} =\]
\[= 1^{n} = 1\]
\[\textbf{б)}\ ( - 1)^{2n}\text{\ \ }:( - 1)^{3} = 1\ :( - 1) =\]
\[= - 1\ \]