Question

Aflati produsul numerelor care impäruite la 8 dau la cât si la rest acelaşi număr.​

Answer 1

Salut! :)

x : 8 = 0 rest 0 => x = 8 × 0 + 0 = 0

x : 8 = 1 rest 1 => x = 8 + 1 + 1 = 9

x : 8 = 2 rest 2 => x = 8 × 2 + 2 = 18

x : 8 = 3 rest 3 => x = 8 × 3 + 3 = 27

x : 8 = 4 rest 4 => x = 8 × 4 + 4 = 36

x : 8 = 5 rest 5 => x = 8 × 5 + 5 = 45

x : 8 = 6 rest 6 => x = 8 × 6 + 6 = 54

x : 8 = 7 rest 7 => x = 8 × 7 + 7 = 63

0 × 9 × 18 × 27 × 36 × 45 × 54 × 63 = 0

Answer 2

$\it n:8=c\ \ rest\ \ c \Rightarrow n=8c+c \Rightarrow n=9c,\ unde \ \ c<8\\ \\ Deci,\ \ n\in\{0,\ 9,\ 18,\ 27,\ 36,\ 45,\ 54,\ 63\}$