33) (a³)-⁵ : a⁻¹⁸, a=2

1. Simplify the first term: a⁻¹⁵ : a⁻¹⁸.
2. Use the rule of exponents aⁿ / aᵐ = aⁿ⁻ᵐ: a⁻¹⁵⁻⁽⁻¹⁸⁾ = a⁻¹⁵⁺¹⁸ = a³.
3. Substitute a=2: 2³ = 8.