\[\boxed{\text{960.}\text{\ }еуроки - ответы\ на\ пятёрку}\]
\[\textbf{а)}\ x² - 2xc + c^{2} - d^{2} =\]
\[= (x - c)^{2} - d^{2} =\]
\[= (x - c - d)(x - c + d)\]
\[\textbf{б)}\ c² + 2c + 1 - a^{2} =\]
\[= (c + 1)^{2} - a^{2} =\]
\[= (c + 1 - a)(c + 1 + a)\]
\[\textbf{в)}\ p² - x^{2} + 6x - 9 =\]
\[= p^{2} - \left( x^{2} - 6x + 9 \right) =\]
\[= p^{2} - (x - 3)^{2} =\]
\[= (p - x + 3)(p + x - 3)\]
\[\textbf{г)}\ x² - a^{2} - 10a - 25 =\]
\[= x^{2} - \left( a^{2} + 10a + 25 \right) =\]
\[= x^{2} - (a + 5)^{2} =\]
\[= (x - a - 5)(x + a + 5)\ \]