а) (a⁻⁵)² × a¹² = a⁻⁵ˣ² × a¹² = a⁻¹⁰ × a¹² = a⁻¹⁰⁺¹² = a² = a²
б) 0,5ab⁻³ × 4a⁻²b⁴ = 0,5 × 4 × a¹⁻² × b⁻³⁺⁴ = 2 × a⁻¹ × b¹ = 2 × (1/a) × b = 2b/a