x = 1/5, y = 25
125 * (1/5)⁻³ * 25⁻⁴
(1/5)⁻³ = 5³ = 125
25⁻⁴ = 1/25⁴
125 * 125 * 1/25⁴ = 125² * 1/25⁴ = 5⁶ * 1/5⁸ = 1/5² = 1/25