5⁷/ 25² * 5⁻² = 5⁷/ 5⁴ * 1/5² = 5⁷/ (5⁴ *5²)=5⁷⁻⁶ = 5
(3⁻⁴ * 3⁻⁹)/ 9⁻⁶ = 3⁻¹³ / 3⁻¹² = 3⁻¹³⁺¹² = 3⁻¹ = 1/3
