Resposta :
Răspuns:
x = 9 ; y = 9
Explicație pas cu pas:
__ __ ___ ____
(xx + yy + xyx + xyyx) /4 = 2799 =>
10x+x + 10y+y + 100x+10y+x + 1000x+100y+10y+x = 2799·4
1113x + 131y = 11196
x = 9 => 1113x = 10017 =>
131y = 11196-10017 = 1179 => y = 1179/131 => y = 9
ma (99 ; 99 ; 999 ; 9999) = (99+99+999+9999)/4 =
= 11196/4 = 2799 , corect