вправа 715 гдз 7 клас алгебра Мерзляк Полонський

Відповідь: \begin{equation}1)a^{7}+ab^{6}=\end{equation} \begin{equation}=a\left ( a^{6}+b^{6} \right )=\end{equation} \begin{equation}=a\left ( a^{2}+b^{2} \right )\left ( a^{4}+a^{2}b^{2}+b^{4} \right );\end{equation} \begin{equation}2)x^{8}-y^{8}=\end{equation} \begin{equation}=\left ( x^{4}-y^{4} \right )\left ( x^{4}+y^{4} \right )=\end{equation} \begin{equation}=\left ( x^{2}-y^{2} \right )\left ( x^{2}+y^{2} \right )\end{equation} \begin{equation}\left ( x^{4}+y^{4} \right )=\end{equation} \begin{equation}=\left ( x-y \right )\left ( x+y \right )\left ( x^{2}+y^{2} \right )\end{equation} \begin{equation}\left ( x^{4}+y^{4} \right );\end{equation} \begin{equation}3)c^{6}+1=\left ( c^{3}-1 \right )\left ( c^{3}+1 \right )=\end{equation} \begin{equation}=\left ( c-1 \right )\left ( c^{2}+c+1 \right )\end{equation} \begin{equation}\left ( c+1 \right )\left ( c^{2}-c+1 \right )=\end{equation} \begin{equation}=\left ( c^{2}-1\right )\left ( c^{2}+c+1 \right )\left ( c^{2}-c+1 \right ).\end{equation}