\[\boxed{\text{961.}\text{\ }еуроки - ответы\ на\ пятёрку}\]
\[\textbf{а)}\ x² + 2xy + y² - m^{2} =\]
\[= (x + y)^{2} - m^{2} =\]
\[= (x + y - m)(x + y + m)\]
\[\textbf{б)}\ p² - a^{2} - 2ab - b^{2} =\]
\[= p^{2} - \left( a^{2} + 2ab + b^{2} \right) =\]
\[= p^{2} - (a + b)^{2} =\]
\[= (p - a - b)(p + a + b)\]
\[\textbf{в)}\ b² - c^{2} - 8b + 16 =\]
\[= (b - 4)^{2} - c^{2} =\]
\[= (b - 4 - c)(b - 4 + c)\]
\[\textbf{г)}\ 9 - c^{2} + a^{2} - 6a =\]
\[= (a - 3)^{2} - c^{2} =\]
\[= (a - 3 - c)(a - 3 + c)\ \]