5⁴ : 5² + 5 x ( 55¹ - X : 5 ) = 5³
5 ⁽ ⁴ ⁻ ²⁾ + 5 x ( 55 - X : 5 ) = 125
5² + 5 x ( 55 - X : 5 ) = 125
5 x ( 55 - X : 5 ) = 125 - 25
55 - X : 5 = 100 : 5
55 - X : 5 = 20
X : 5 = 55 - 20
X : 5 = 35
X = 35 × 5
X = 175 → numarul, aflat prin metoda mersului invers