Răspuns:
[tex]aa + bb = 121 \\ \\ 10a + a + 10b + b = 121 \\ \\ 11a + 11b = 121 \\ \\ 11(a + b) = 121 \\ \\ a + b = 121 \div 11 = \\ \\ = 11[/tex]
Succes! ♡︎♥︎♡︎