X=5²⁰¹⁹ + 6²⁰¹⁹
U ( 5²⁰¹⁹ ) =5
U (6²⁰¹⁹ ) = 6
=>U (X )=U (6+5)=U (11) = 1
R : C. 1.
Sper ca te am ajutat!