\[\boxed{\text{685\ (685).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
Пояснение.
Решение.
\[\textbf{а)}\ y^{2}(y + 5)(y - 3) =\]
\[= y^{2}\left( y^{2} - 3y + 5y - 15 \right) =\]
\[= y^{2}\left( y^{2} + 2y - 15 \right) =\]
\[= y^{4} + 2y^{3} - 15y^{2}\]
\[\textbf{б)}\ 2a^{2}(a - 1)(3 - a) =\]
\[= 2a^{2}\left( 3a - a^{2} - 3 + a \right) =\]
\[= 2a^{2}\left( - a^{2} + 4a - 3 \right) =\]
\[= - 2a^{4} + 8a^{3} - 6a^{2}\]
\[\textbf{в)} - 3b^{3}(b + 2)(1 - b) =\]
\[= - 3b^{2}\left( b - b^{2} + 2 - 2b \right) =\]
\[= - 3b^{3}\left( - b^{2} - b + 2 \right) =\]
\[= 3b^{5} + 3b^{4} - 6b^{3}\]
\[\textbf{г)} - 0,5c^{2}(2c - 3)\left( 4 - c^{2} \right) =\]
\[= - 0,5c^{2}\left( 8c - 2c^{3} - 12 + 3c^{2} \right) =\]
\[= c^{5} - 1,5c^{4} - 4c^{3} + 6c^{2}\]