\[\boxed{\text{1011.}\text{\ }еуроки - ответы\ на\ пятёрку}\]
\[\textbf{а)}\ (a - 3)\left( a^{2} - 8a + 5 \right) -\]
\[- (a - 8)\left( a^{2} - 3a + 5 \right) =\]
\[= a^{3} - 8a^{2} + 5a - 3a^{2} + 24a -\]
\[- 15 - a^{3} + 3a^{2} - 5a + 8a^{2} -\]
\[- 24a + 40 = 25\]
\[\textbf{б)}\ \left( x^{2} - 3x + 2 \right)(2x + 5) -\]
\[- \left( 2x^{2} + 7x + 17 \right)(x - 4) =\]
\[= 2x^{3} - 6x^{2} + 4x + 5x^{2} - 15x +\]
\[+ 10 - 2x^{3} - 7x^{2} - 17x +\]
\[+ 8x^{2} + 28x + 68 =\]
\[= 78\]