Răspuns :
a+b+c = 999
a+b = 656
b+c = 504
656+c = 999
c = 999-656
c = 343
a+504 = 999
a = 999-504
a = 495
495+b+343 = 999
b = 999-(495+343)
b = 999-838
b = 161
Verificate
495+161+343 = 656+343 = 999
a+b = 656
b+c = 504
656+c = 999
c = 999-656
c = 343
a+504 = 999
a = 999-504
a = 495
495+b+343 = 999
b = 999-(495+343)
b = 999-838
b = 161
Verificate
495+161+343 = 656+343 = 999
a+b+c=999
a+b=656 => b=656-a
b+c=504 => c=504-b => c=504-656+a => c=a-152
a+656-a+a-152=999 => a=999+-656+152 => a=495
b=161
c=343
a+b=656 => b=656-a
b+c=504 => c=504-b => c=504-656+a => c=a-152
a+656-a+a-152=999 => a=999+-656+152 => a=495
b=161
c=343