Question

-3a² (a³ - a²) - 5a³ (a² + 3a)

Answer 1

Aplicando a distributiva:
-3a5 + 3a4 - 5a5 -15a4

-8a5 - 12a4

Answer 2

Temos que:

$-3a^2(a^3-a^2)=-3a^5+3a^4$

$-5a^3(a^2+3a)=-5a^5-15^4$

Assim:

$-3a^2(a^3-a^2)-5a^3(a^2+3a)=-3a^5+3a^4-5a^5-15a^4=\boxed{-8a^5-12a^4}$.