a) a = 5 la a 2-a la a 6-a = 5⁶⁴
b = 5¹⁶
--------------> a > b
b) 3¹⁵⁰ 5¹⁰⁰
[(3³)²]²⁵ (5⁴)²⁵ am descompus exponentii si observam ca avem 25 25 deci ramane de comparat: (3³)² si (5²)² sau 3³ si 5² sau 27 si 25 evident 3³ > 5² in concluzie a > b
4) U(n) = U(67³⁸ + 92⁴³) = U(67³⁸) + U(92⁴³) = U( 9 + 8 ) = U(17) = 7
