Question

Determina ultima cifra a nr. 3 la puterea 9 + 2 la puterea 9 + 5 la puterea 9. Please Help!! este urgent :3​

Answer 1

$\it u(3^9)=u(3^8\cdot3)=u[(3^4)^2\cdot3]=u(81^2\cdot3)=u(1\cdot3)=3\\ \\ u(2^9)=u(2^8\cdot2)=u[(2^4)^2\cdot2]=u(16^2\cdot2)=u(6\cdot2)=u(12)=2\\ \\ u(5^9)=5$

$\it Deci,\ \ u(3^9+2^9+5^9)=u(3+2+5)=u(10)=0$