a+b+c=58
55a=65=>a=65/55=13/11
a+2b=143(c-b-a)
a+2b=143c-143b-143a
143c-141b-142a=0
143c-141b=142•13/11=1859/11
141(143/141c-b)=1859/11
143c/141-b=1859/1551
143c/141=1859/1551+b
c=141(1859/1551+b)/143(2)
13/11+b+141(1859/1551+b)/143=58(1)
Afla-l pe b din relatia (1), dupa care il afli pe c,inlocuind b in relatia (2).