\[\boxed{\text{1083.}\text{\ }еуроки - ответы\ на\ пятёрку}\]
\[\textbf{а)}\ a³ + a² - x^{2}a - x^{2} =\]
\[= a^{2}(a + 1) - x^{2}(a + 1) =\]
\[= (a + 1)\left( a^{2} - x^{2} \right) =\]
\[= (a + 1)(a - x)(a + x)\]
\[\textbf{б)}\ b³ + b²c - 9b - 9c =\]
\[= b^{2}(b + c) - 9 \cdot (b + c) =\]
\[= (b + c)\left( b^{2} - 9 \right) =\]
\[= (b + c)(b - 3)(b + 3)\]