Question

Determinati nr ab, scris in baza 10, stiind ca ab-ba=a(b-1),unde a si b sunt nr duferite,prome intre ele

Answer 1

ab - ba = a(b-1)

10a + b - 10b - a = a(b-1)

9 (a-b) = a(b-1)

a=9 si  a-b=b-1

=> 9+1=2b

b=5

ab=95

verificare: 95-59=9(5-1)

                 36=36 (A)