Răspuns :
579-12=567 - surplusul
567:7=81 - primul numar
81x3=243 - al doilea numar
243+12=255 - al treilea numar
567:7=81 - primul numar
81x3=243 - al doilea numar
243+12=255 - al treilea numar
[tex]x+y+z=579 \\ y=3x \\ z=y+12 \\ z=3x+12 \\ x+3x+3x+12=579 \\ 7x+12=579 \\ 7x=579-12 \\ 7x=567 \\ x=\frac{567}7} \\ \boxed{\bold{x=81}} \\ y=3x=3 \cdot 81 \\ \boxed{\bold{y=243}} \\ z=y+12 =243+12 \\ \boxed{\bold{z=255}}[/tex]