a + b + c = 1377
a : b = 4 rest 21
a = 4b + 21
c = b : 4 - 9
inlocuim in prima relatie in functie de b
4b + 21 + b + b : 4 - 9 = 1377
5b + b : 4 = 1377 - 21 + 9
5b + b : 4 = 1 365 |×4
20b + b = 5460
21b = 5460
b = 5460:21
b = 260
a = 4×260+21 = 1040 + 21 = 1061
c = 260:4 -9 = 65-9 = 56
verificare:
1061 + 260 + 56 = 1377
solutiile sunt:
a = 1061
b = 260
c = 56