Преобразуем каждое выражение в одночлен стандартного вида:
-5x³y⁷ ⋅ 3x⁵y³ = (-5 ⋅ 3) ⋅ (x³ ⋅ x⁵) ⋅ (y⁷ ⋅ y³) = -15x^(3+5)y^(7+3) = -15x⁸y¹⁰
(-8a³n)³ = (-8)³ ⋅ (a³ )³ ⋅ n³ = -512a^(3⋅3)n³ = -512a⁹n³