\[\boxed{\text{608\ (608).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[\textbf{а)}\ x^{3} + 2x^{2} - 3x - 5 =\]
\[= - 3x - (5 - x^{3} - 2x^{2})\]
\[\textbf{б)}\ 3a^{4} + 2a^{3} + 5a^{2} - 4 =\]
\[= 5a^{2} - (4 - 3a^{4} - 2a^{3})\ \]