\[\boxed{\text{1201\ (1201).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[n(n - 1)(n + 1) + n =\]
\[= n\left( (n - 1)(n + 1) + 1 \right) =\]
\[= n\left( n^{2} - 1 + 1 \right) = n \cdot n^{2} = n^{3}\ \]
\[\boxed{\text{1201.\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[M\ (6;0);\ \ K\ (0;6):\]
\[y = kx + b\]
\[0 = 6k + b\]
\[6 = 0 + b \Longrightarrow \ b = 6\]
\[6k = - 6 \Longrightarrow \ k = - 1\]
\[y = - x + 6\]
\[y + x = 6.\]