Răspuns :
a+b=564 => a=564-b
a+a+b=785 => 2a+b=785
2(564-b)+b=785 => 1128-2b+b=785 => 1128-b=785 => 1128-785=b => b=343
a=564-343=221 => a=221
a+a+b=785 => 2a+b=785
2(564-b)+b=785 => 1128-2b+b=785 => 1128-b=785 => 1128-785=b => b=343
a=564-343=221 => a=221
[tex] -\left \{ {{a+b=564} \atop {a+a+b=785}} \right. =\ \textgreater \ a=785-564 \\ a=221
a+b=564 \\ 221+b=564 \\ b=564-221 \\ b=343[/tex]