\[\boxed{\text{821.}\text{\ }еуроки - ответы\ на\ пятёрку}\]
\[\textbf{а)}\ ( - x + 5)^{2} = ( - x)^{2} - 2 \cdot 5x +\]
\[+ 5^{2} = x^{2} - 10x + 25\]
\[\textbf{б)}\ ( - z - 2)^{2} = ( - z)^{2} + 2 \cdot\]
\[\cdot 2z + ( - 2)^{2} = z² + 4z + 4\]
\[\textbf{в)}\ ( - n + 4)^{2} = ( - n)^{2} - 2 \cdot 4 \cdot\]
\[\cdot n + 4^{2} = n^{2} - 8n + 16\]
\[\textbf{г)}\ ( - m - 10)² = ( - m)^{2} + 2 \cdot\]
\[\cdot 10m + ( - 10)^{2} = m^{2} +\]
\[+ 20m + 100\ \]